diff --git a/cont/base/springcontent/LuaGadgets/callins.lua b/cont/base/springcontent/LuaGadgets/callins.lua
index d5b212d6eac..312b0945c7a 100644
--- a/cont/base/springcontent/LuaGadgets/callins.lua
+++ b/cont/base/springcontent/LuaGadgets/callins.lua
@@ -102,6 +102,8 @@ CALLIN_LIST = {
 	"AllowUnitTransfer",
 	"AllowUnitBuildStep",
 	"AllowUnitTransport",
+	"AllowUnitTransportLoad",
+	"AllowUnitTransportUnload",
 	"AllowUnitCloak",
 	"AllowUnitDecloak",
 	"AllowFeatureBuildStep",
diff --git a/cont/base/springcontent/LuaGadgets/gadgets.lua b/cont/base/springcontent/LuaGadgets/gadgets.lua
index de6e77620bd..dbbc203e1dc 100644
--- a/cont/base/springcontent/LuaGadgets/gadgets.lua
+++ b/cont/base/springcontent/LuaGadgets/gadgets.lua
@@ -1138,14 +1138,47 @@ function gadgetHandler:AllowUnitTransport(
   transporteeID, transporteeUnitDefID, transporteeTeam
 )
   for _,g in r_ipairs(self.AllowUnitTransportList) do
-    if (not g:AllowUnitTransport(transporterID, transporterUnitDefID, transporterTeam,
-                                 transporteeID, transporteeUnitDefID, transporteeTeam)) then
+    if (not g:AllowUnitTransport(
+      transporterID, transporterUnitDefID, transporterTeam,
+      transporteeID, transporteeUnitDefID, transporteeTeam
+    )) then
       return false
     end
   end
   return true
 end
 
+function gadgetHandler:AllowUnitTransportLoad(
+  transporterID, transporterUnitDefID, transporterTeam,
+  transporteeID, transporteeUnitDefID, transporteeTeam
+)
+  for _,g in r_ipairs(self.AllowUnitTransportLoadList) do
+    if (not g:AllowUnitTransportLoad(
+      transporterID, transporterUnitDefID, transporterTeam,
+      transporteeID, transporteeUnitDefID, transporteeTeam
+    )) then
+      return false
+    end
+  end
+  return true
+end
+
+function gadgetHandler:AllowUnitTransportUnload(
+  transporterID, transporterUnitDefID, transporterTeam,
+  transporteeID, transporteeUnitDefID, transporteeTeam
+)
+  for _,g in r_ipairs(self.AllowUnitTransportUnloadList) do
+    if (not g:AllowUnitTransportUnload(
+      transporterID, transporterUnitDefID, transporterTeam,
+      transporteeID, transporteeUnitDefID, transporteeTeam
+    )) then
+      return false
+    end
+  end
+  return true
+end
+
+
 function gadgetHandler:AllowUnitCloak(unitID, enemyID)
   for _,g in r_ipairs(self.AllowUnitCloakList) do
     if (not g:AllowUnitCloak(unitID, enemyID)) then
diff --git a/rts/Lua/LuaHandleSynced.cpp b/rts/Lua/LuaHandleSynced.cpp
index f11ddfbe219..fb6efee7f05 100644
--- a/rts/Lua/LuaHandleSynced.cpp
+++ b/rts/Lua/LuaHandleSynced.cpp
@@ -207,9 +207,9 @@ bool CUnsyncedLuaHandle::DrawUnit(const CUnit* unit)
 	if (!success)
 		return false;
 
-	const bool retval = luaL_optboolean(L, -1, false);
+	const bool draw = luaL_optboolean(L, -1, false);
 	lua_pop(L, 1);
-	return retval;
+	return draw;
 }
 
 
@@ -234,9 +234,9 @@ bool CUnsyncedLuaHandle::DrawFeature(const CFeature* feature)
 	if (!success)
 		return false;
 
-	const bool retval = luaL_optboolean(L, -1, false);
+	const bool draw = luaL_optboolean(L, -1, false);
 	lua_pop(L, 1);
-	return retval;
+	return draw;
 }
 
 
@@ -263,9 +263,9 @@ bool CUnsyncedLuaHandle::DrawShield(const CUnit* unit, const CWeapon* weapon)
 	if (!success)
 		return false;
 
-	const bool retval = luaL_optboolean(L, -1, false);
+	const bool draw = luaL_optboolean(L, -1, false);
 	lua_pop(L, 1);
-	return retval;
+	return draw;
 }
 
 
@@ -292,9 +292,9 @@ bool CUnsyncedLuaHandle::DrawProjectile(const CProjectile* projectile)
 	if (!success)
 		return false;
 
-	const bool retval = luaL_optboolean(L, -1, false);
+	const bool draw = luaL_optboolean(L, -1, false);
 	lua_pop(L, 1);
-	return retval;
+	return draw;
 }
 
 
@@ -475,9 +475,9 @@ bool CSyncedLuaHandle::CommandFallback(const CUnit* unit, const Command& cmd)
 	if (!RunCallIn(L, cmdStr, 7, 1))
 		return true;
 
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool remove = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval; // return 'true' to remove the command
+	return remove; // return 'true' to remove the command
 }
 
 
@@ -499,9 +499,9 @@ bool CSyncedLuaHandle::AllowCommand(const CUnit* unit, const Command& cmd, bool
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -531,9 +531,9 @@ bool CSyncedLuaHandle::AllowUnitCreation(const UnitDef* unitDef,
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -558,9 +558,9 @@ bool CSyncedLuaHandle::AllowUnitTransfer(const CUnit* unit, int newTeam, bool ca
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -585,21 +585,21 @@ bool CSyncedLuaHandle::AllowUnitBuildStep(const CUnit* builder,
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
 bool CSyncedLuaHandle::AllowUnitTransport(const CUnit* transporter, const CUnit* transportee)
 {
 	LUA_CALL_IN_CHECK(L, true);
-	luaL_checkstack(L, 8, __func__);
+	luaL_checkstack(L, 2 + 6, __func__);
 
 	static const LuaHashString cmdStr(__func__);
 
 	if (!cmdStr.GetGlobalFunc(L))
-		return true; // the call is not defined
+		return true;
 
 	lua_pushnumber(L, transporter->id);
 	lua_pushnumber(L, transporter->unitDef->id);
@@ -608,14 +608,62 @@ bool CSyncedLuaHandle::AllowUnitTransport(const CUnit* transporter, const CUnit*
 	lua_pushnumber(L, transportee->unitDef->id);
 	lua_pushnumber(L, transportee->team);
 
-	// call the function
 	if (!RunCallIn(L, cmdStr, 6, 1))
 		return true;
 
-	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
+	lua_pop(L, 1);
+	return allow;
+}
+
+bool CSyncedLuaHandle::AllowUnitTransportLoad(const CUnit* transporter, const CUnit* transportee, bool allowed)
+{
+	LUA_CALL_IN_CHECK(L, true);
+	luaL_checkstack(L, 2 + 6, __func__);
+
+	static const LuaHashString cmdStr(__func__);
+
+	if (!cmdStr.GetGlobalFunc(L))
+		return allowed;
+
+	lua_pushnumber(L, transporter->id);
+	lua_pushnumber(L, transporter->unitDef->id);
+	lua_pushnumber(L, transporter->team);
+	lua_pushnumber(L, transportee->id);
+	lua_pushnumber(L, transportee->unitDef->id);
+	lua_pushnumber(L, transportee->team);
+
+	if (!RunCallIn(L, cmdStr, 6, 1))
+		return true;
+
+	const bool allow = luaL_optboolean(L, -1, allowed);
+	lua_pop(L, 1);
+	return allow;
+}
+
+bool CSyncedLuaHandle::AllowUnitTransportUnload(const CUnit* transporter, const CUnit* transportee, bool allowed)
+{
+	LUA_CALL_IN_CHECK(L, true);
+	luaL_checkstack(L, 2 + 6, __func__);
+
+	static const LuaHashString cmdStr(__func__);
+
+	if (!cmdStr.GetGlobalFunc(L))
+		return allowed;
+
+	lua_pushnumber(L, transporter->id);
+	lua_pushnumber(L, transporter->unitDef->id);
+	lua_pushnumber(L, transporter->team);
+	lua_pushnumber(L, transportee->id);
+	lua_pushnumber(L, transportee->unitDef->id);
+	lua_pushnumber(L, transportee->team);
+
+	if (!RunCallIn(L, cmdStr, 6, 1))
+		return true;
+
+	const bool allow = luaL_optboolean(L, -1, allowed);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -641,9 +689,9 @@ bool CSyncedLuaHandle::AllowUnitCloak(const CUnit* unit, const CUnit* enemy)
 	if (!RunCallIn(L, cmdStr, 2, 1))
 		return true;
 
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 bool CSyncedLuaHandle::AllowUnitDecloak(const CUnit* unit, const CSolidObject* object, const CWeapon* weapon)
@@ -675,9 +723,9 @@ bool CSyncedLuaHandle::AllowUnitDecloak(const CUnit* unit, const CSolidObject* o
 
 	assert(lua_isboolean(L, -1));
 
-	const bool retval = lua_toboolean(L, -1);
+	const bool allow = lua_toboolean(L, -1);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -701,9 +749,9 @@ bool CSyncedLuaHandle::AllowFeatureCreation(const FeatureDef* featureDef, int te
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -727,9 +775,9 @@ bool CSyncedLuaHandle::AllowFeatureBuildStep(const CUnit* builder, const CFeatur
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -751,9 +799,9 @@ bool CSyncedLuaHandle::AllowResourceLevel(int teamID, const string& type, float
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -776,9 +824,9 @@ bool CSyncedLuaHandle::AllowResourceTransfer(int oldTeam, int newTeam, const cha
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -801,9 +849,9 @@ bool CSyncedLuaHandle::AllowDirectUnitControl(int playerID, const CUnit* unit)
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -825,9 +873,9 @@ bool CSyncedLuaHandle::AllowBuilderHoldFire(const CUnit* unit, int action)
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -856,9 +904,9 @@ bool CSyncedLuaHandle::AllowStartPosition(int playerID, int teamID, unsigned cha
 		return true;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, true);
+	const bool allow = luaL_optboolean(L, -1, true);
 	lua_pop(L, 1);
-	return retval;
+	return allow;
 }
 
 
@@ -882,9 +930,9 @@ bool CSyncedLuaHandle::MoveCtrlNotify(const CUnit* unit, int data)
 		return false;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, false);
+	const bool disable = luaL_optboolean(L, -1, false);
 	lua_pop(L, 1);
-	return retval;
+	return disable;
 }
 
 
@@ -914,9 +962,9 @@ bool CSyncedLuaHandle::TerraformComplete(const CUnit* unit, const CUnit* build)
 		return false;
 
 	// get the results
-	const bool retval = luaL_optboolean(L, -1, false);
+	const bool stop = luaL_optboolean(L, -1, false);
 	lua_pop(L, 1);
-	return retval;
+	return stop;
 }
 
 
diff --git a/rts/Lua/LuaHandleSynced.h b/rts/Lua/LuaHandleSynced.h
index ffd184c2319..308f4b428ce 100644
--- a/rts/Lua/LuaHandleSynced.h
+++ b/rts/Lua/LuaHandleSynced.h
@@ -59,6 +59,8 @@ class CSyncedLuaHandle : public CLuaHandle
 		bool AllowUnitTransfer(const CUnit* unit, int newTeam, bool capture) override;
 		bool AllowUnitBuildStep(const CUnit* builder, const CUnit* unit, float part) override;
 		bool AllowUnitTransport(const CUnit* transporter, const CUnit* transportee) override;
+		bool AllowUnitTransportLoad(const CUnit* transporter, const CUnit* transportee, bool allowed) override;
+		bool AllowUnitTransportUnload(const CUnit* transporter, const CUnit* transportee, bool allowed) override;
 		bool AllowUnitCloak(const CUnit* unit, const CUnit* enemy) override;
 		bool AllowUnitDecloak(const CUnit* unit, const CSolidObject* object, const CWeapon* weapon) override;
 		bool AllowFeatureCreation(const FeatureDef* featureDef, int allyTeamID, const float3& pos) override;
diff --git a/rts/Sim/Units/CommandAI/MobileCAI.cpp b/rts/Sim/Units/CommandAI/MobileCAI.cpp
index 8ffca29e068..21536e6e7fe 100644
--- a/rts/Sim/Units/CommandAI/MobileCAI.cpp
+++ b/rts/Sim/Units/CommandAI/MobileCAI.cpp
@@ -21,6 +21,7 @@
 #include "Sim/Weapons/Weapon.h"
 #include "Sim/Weapons/WeaponDef.h"
 #include "System/Log/ILog.h"
+#include "System/EventHandler.h"
 #include "System/myMath.h"
 #include "System/StringUtil.h"
 #include <assert.h>
@@ -1336,12 +1337,18 @@ void CMobileCAI::ExecuteLoadUnits(Command& c)
 			}
 
 			if (inCommand) {
-				if (!owner->script->IsBusy()) {
+				if (!owner->script->IsBusy())
 					StopMoveAndFinishCommand();
-				}
+
+				return;
+			}
+
+			if (!owner->CanTransport(unit) || !UpdateTargetLostTimer(int(c.params[0]))) {
+				StopMoveAndFinishCommand();
 				return;
 			}
-			if (owner->CanTransport(unit) && UpdateTargetLostTimer(int(c.params[0]))) {
+
+			{
 				SetTransportee(unit);
 
 				const float sqDist = unit->pos.SqDistance2D(owner->pos);
@@ -1379,33 +1386,40 @@ void CMobileCAI::ExecuteLoadUnits(Command& c)
 						const bool b2 = (std::abs(owner->heading - unit->heading) < AIRTRANSPORT_DOCKING_ANGLE);
 						const bool b3 = (owner->updir.dot(UpVector) > 0.995f);
 
-						if (b1 && b2 && b3) {
-							am->SetAllowLanding(false);
-							am->SetWantedAltitude(0.0f);
+						if (!eventHandler.AllowUnitTransportLoad(owner, unit, b1 && b2 && b3))
+							return;
 
-							owner->script->BeginTransport(unit);
-							SetTransportee(nullptr);
-							owner->AttachUnit(unit, owner->script->QueryTransport(unit));
+						am->SetAllowLanding(false);
+						am->SetWantedAltitude(0.0f);
 
-							StopMoveAndFinishCommand();
-							return;
-						}
+						owner->script->BeginTransport(unit);
+						SetTransportee(nullptr);
+						owner->AttachUnit(unit, owner->script->QueryTransport(unit));
+
+						StopMoveAndFinishCommand();
 					} else {
+						if (!eventHandler.AllowUnitTransportLoad(owner, unit, true))
+							return;
+
 						inCommand = true;
 
 						StopMove();
 						owner->script->TransportPickup(unit);
 					}
-				} else if (owner->moveType->progressState == AMoveType::Failed && sqDist < (200 * 200)) {
-					// if we're pretty close already but CGroundMoveType fails because it considers
-					// the goal clogged (with the future passenger...), just try to move to the
-					// point halfway between the transport and the passenger.
-					SetGoal((unit->pos + owner->pos) * 0.5f, owner->pos);
+
+					return;
 				}
-			} else {
-				StopMoveAndFinishCommand();
+
+				if (owner->moveType->progressState != AMoveType::Failed || sqDist >= Square(200.0f))
+					return;
+
+				// if we're pretty close already but CGroundMoveType fails because it considers
+				// the goal clogged (with the future passenger...), just try to move to the
+				// point halfway between the transport and the passenger.
+				SetGoal((unit->pos + owner->pos) * 0.5f, owner->pos);
 			}
 		} break;
+
 		case 4: {
 			// area-load, avoid infinite loops
 			if (lastCommandFrame == gs->frameNum)
@@ -1518,7 +1532,7 @@ bool CMobileCAI::AllowedCommand(const Command& c, bool fromSynced)
 			if (c.GetParamsCount() == 5) {
 				if (fromSynced) {
 					// point transported buildings (...) in their wanted direction after unloading
-					for (auto& tu: transportees) {
+					for (const CUnit::TransportedUnit& tu: transportees) {
 						tu.unit->buildFacing = std::abs(int(c.GetParam(4))) % NUM_FACINGS;
 					}
 				}
@@ -1526,7 +1540,7 @@ bool CMobileCAI::AllowedCommand(const Command& c, bool fromSynced)
 
 			if (c.GetParamsCount() >= 4) {
 				// find unload positions for transportees (WHY can this run in unsynced context?)
-				for (const auto& tu: transportees) {
+				for (const CUnit::TransportedUnit& tu: transportees) {
 					const CUnit* u = tu.unit;
 
 					const float radius = (c.GetID() == CMD_UNLOAD_UNITS)? c.GetParam(3): 0.0f;
@@ -1863,7 +1877,7 @@ void CMobileCAI::UnloadLand(Command& c)
 		const int unitID = c.params[3];
 
 		// unload a specific transportee
-		for (auto& tu: transportees) {
+		for (const CUnit::TransportedUnit& tu: transportees) {
 			CUnit* carried = tu.unit;
 
 			if (unitID == carried->id) {
@@ -1877,55 +1891,64 @@ void CMobileCAI::UnloadLand(Command& c)
 		}
 	}
 
-	if (wantedPos.SqDistance2D(owner->pos) < Square(owner->unitDef->loadingRadius * 0.9f)) {
-		wantedPos.y = owner->GetTransporteeWantedHeight(wantedPos, transportee);
+	if (wantedPos.SqDistance2D(owner->pos) >= Square(owner->unitDef->loadingRadius * 0.9f))
+		return;
 
-		if ((am = dynamic_cast<CHoverAirMoveType*>(owner->moveType)) != nullptr) {
-			// handle air transports differently
-			SetGoal(wantedPos, owner->pos);
+	wantedPos.y = owner->GetTransporteeWantedHeight(wantedPos, transportee);
 
-			am->SetWantedAltitude(wantedPos.y - CGround::GetHeightAboveWater(wantedPos.x, wantedPos.z));
-			am->ForceHeading(owner->GetTransporteeWantedHeading(transportee));
+	if ((am = dynamic_cast<CHoverAirMoveType*>(owner->moveType)) == nullptr) {
+		if (!eventHandler.AllowUnitTransportUnload(owner, transportee, true))
+			return;
 
-			am->maxDrift = 1.0f;
+		inCommand = true;
 
-			// FIXME: kill the hardcoded constants, use the command's radius
-			// NOTE: 2D distance-check would mean units get dropped from air
-			const bool b1 = (owner->pos.SqDistance(wantedPos) < Square(AIRTRANSPORT_DOCKING_RADIUS));
-			const bool b2 = (std::abs(owner->heading - am->GetForcedHeading()) < AIRTRANSPORT_DOCKING_ANGLE);
-			const bool b3 = (owner->updir.dot(UpVector) > 0.99f);
+		StopMove();
+		owner->script->TransportDrop(transportee, wantedPos);
+		return;
+	}
 
-			if (b1 && b2 && b3) {
-				wantedPos.y -= transportee->radius;
+	{
+		// handle air transports differently
+		SetGoal(wantedPos, owner->pos);
 
-				if (!SpotIsClearIgnoreSelf(wantedPos, transportee)) {
-					// chosen spot is no longer clear to land, choose a new one
-					// if a new spot cannot be found, don't unload at all
-					float3 newWantedPos;
+		am->SetWantedAltitude(wantedPos.y - CGround::GetHeightAboveWater(wantedPos.x, wantedPos.z));
+		am->ForceHeading(owner->GetTransporteeWantedHeading(transportee));
 
-					if (FindEmptySpot(transportee, wantedPos, std::max(16.0f * SQUARE_SIZE, transportee->radius * 4.0f), transportee->radius, newWantedPos)) {
-						c.SetPos(0, newWantedPos);
-						SetGoal(newWantedPos + UpVector * transportee->model->height, owner->pos);
-						return;
-					}
-				} else {
-					owner->DetachUnit(transportee);
+		am->maxDrift = 1.0f;
 
-					if (transportees.empty()) {
-						am->SetAllowLanding(true);
-						owner->script->EndTransport();
-					}
-				}
+		// FIXME: kill the hardcoded constants, use the command's radius
+		// NOTE: 2D distance-check would mean units get dropped from air
+		const bool b1 = (owner->pos.SqDistance(wantedPos) < Square(AIRTRANSPORT_DOCKING_RADIUS));
+		const bool b2 = (std::abs(owner->heading - am->GetForcedHeading()) < AIRTRANSPORT_DOCKING_ANGLE);
+		const bool b3 = (owner->updir.dot(UpVector) > 0.99f);
 
-				// move the transport away slightly
-				SetGoal(owner->pos + owner->frontdir * 20.0f, owner->pos);
-				FinishCommand();
+		if (!eventHandler.AllowUnitTransportUnload(owner, transportee, b1 && b2 && b3))
+			return;
+
+		wantedPos.y -= transportee->radius;
+
+		if (!SpotIsClearIgnoreSelf(wantedPos, transportee)) {
+			// chosen spot is no longer clear to land, choose a new one
+			// if a new spot cannot be found, don't unload at all
+			float3 newWantedPos;
+
+			if (FindEmptySpot(transportee, wantedPos, std::max(16.0f * SQUARE_SIZE, transportee->radius * 4.0f), transportee->radius, newWantedPos)) {
+				c.SetPos(0, newWantedPos);
+				SetGoal(newWantedPos + UpVector * transportee->model->height, owner->pos);
+				return;
 			}
 		} else {
-			inCommand = true;
-			StopMove();
-			owner->script->TransportDrop(transportee, wantedPos);
+			owner->DetachUnit(transportee);
+
+			if (transportees.empty()) {
+				am->SetAllowLanding(true);
+				owner->script->EndTransport();
+			}
 		}
+
+		// move the transport away slightly
+		SetGoal(owner->pos + owner->frontdir * 20.0f, owner->pos);
+		FinishCommand();
 	}
 }
 
@@ -1981,7 +2004,7 @@ void CMobileCAI::UnloadLandFlood(Command& c)
 	} else {
 		const int unitID = c.params[3];
 
-		for (auto& tu: transportees) {
+		for (const CUnit::TransportedUnit& tu: transportees) {
 			CUnit* carried = tu.unit;
 
 			if (unitID == carried->id) {
diff --git a/rts/System/EventClient.h b/rts/System/EventClient.h
index a4cec1cb1aa..aa3e7a3c3ab 100644
--- a/rts/System/EventClient.h
+++ b/rts/System/EventClient.h
@@ -201,6 +201,8 @@ class CEventClient
 		virtual bool AllowUnitTransfer(const CUnit* unit, int newTeam, bool capture) { return true; }
 		virtual bool AllowUnitBuildStep(const CUnit* builder, const CUnit* unit, float part) { return true; }
 		virtual bool AllowUnitTransport(const CUnit* transporter, const CUnit* transportee) { return true; }
+		virtual bool AllowUnitTransportLoad(const CUnit* transporter, const CUnit* transportee, bool allowed) { return true; }
+		virtual bool AllowUnitTransportUnload(const CUnit* transporter, const CUnit* transportee, bool allowed) { return true; }
 		virtual bool AllowUnitCloak(const CUnit* unit, const CUnit* enemy) { return true; }
 		virtual bool AllowUnitDecloak(const CUnit* unit, const CSolidObject* object, const CWeapon* weapon) { return true; }
 		virtual bool AllowFeatureCreation(const FeatureDef* featureDef, int allyTeamID, const float3& pos) { return true; }
diff --git a/rts/System/EventHandler.cpp b/rts/System/EventHandler.cpp
index a99ccf43ebc..f1f7a85e93f 100644
--- a/rts/System/EventHandler.cpp
+++ b/rts/System/EventHandler.cpp
@@ -272,6 +272,16 @@ bool CEventHandler::AllowUnitTransport(const CUnit* transporter, const CUnit* tr
 	return ControlIterateDefTrue(listAllowUnitTransport, &CEventClient::AllowUnitTransport, transporter, transportee);
 }
 
+bool CEventHandler::AllowUnitTransportLoad(const CUnit* transporter, const CUnit* transportee, bool allowed)
+{
+	return ControlIterateDefTrue(listAllowUnitTransportLoad, &CEventClient::AllowUnitTransportLoad, transporter, transportee, allowed);
+}
+
+bool CEventHandler::AllowUnitTransportUnload(const CUnit* transporter, const CUnit* transportee, bool allowed)
+{
+	return ControlIterateDefTrue(listAllowUnitTransportUnload, &CEventClient::AllowUnitTransportUnload, transporter, transportee, allowed);
+}
+
 bool CEventHandler::AllowUnitCloak(const CUnit* unit, const CUnit* enemy)
 {
 	return ControlIterateDefTrue(listAllowUnitCloak, &CEventClient::AllowUnitCloak, unit, enemy);
diff --git a/rts/System/EventHandler.h b/rts/System/EventHandler.h
index b7bea6c04d6..95fcc0874f5 100644
--- a/rts/System/EventHandler.h
+++ b/rts/System/EventHandler.h
@@ -140,6 +140,8 @@ class CEventHandler
 		bool AllowUnitTransfer(const CUnit* unit, int newTeam, bool capture);
 		bool AllowUnitBuildStep(const CUnit* builder, const CUnit* unit, float part);
 		bool AllowUnitTransport(const CUnit* transporter, const CUnit* transportee);
+		bool AllowUnitTransportLoad(const CUnit* transporter, const CUnit* transportee, bool allowed);
+		bool AllowUnitTransportUnload(const CUnit* transporter, const CUnit* transportee, bool allowed);
 		bool AllowUnitCloak(const CUnit* unit, const CUnit* enemy);
 		bool AllowUnitDecloak(const CUnit* unit, const CSolidObject* object, const CWeapon* weapon);
 		bool AllowFeatureCreation(const FeatureDef* featureDef, int allyTeamID, const float3& pos);
diff --git a/rts/System/Events.def b/rts/System/Events.def
index 250adb19657..937ed02c657 100644
--- a/rts/System/Events.def
+++ b/rts/System/Events.def
@@ -159,23 +159,25 @@
 
 	SETUP_EVENT(SyncedActionFallback, MANAGED_BIT | CONTROL_BIT)
 
-	SETUP_EVENT(CommandFallback,        MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowCommand,           MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowUnitCreation,      MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowUnitTransfer,      MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowUnitBuildStep,     MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowUnitTransport,     MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowUnitCloak,         MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowUnitDecloak,       MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowFeatureCreation,   MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowFeatureBuildStep,  MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowResourceLevel,     MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowResourceTransfer,  MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowDirectUnitControl, MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowBuilderHoldFire,   MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(AllowStartPosition,     MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(TerraformComplete,      MANAGED_BIT | CONTROL_BIT)
-	SETUP_EVENT(MoveCtrlNotify,         MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(CommandFallback,          MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowCommand,             MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitCreation,        MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitTransfer,        MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitBuildStep,       MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitTransport,       MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitTransportLoad,   MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitTransportUnload, MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitCloak,           MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowUnitDecloak,         MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowFeatureCreation,     MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowFeatureBuildStep,    MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowResourceLevel,       MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowResourceTransfer,    MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowDirectUnitControl,   MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowBuilderHoldFire,     MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(AllowStartPosition,       MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(TerraformComplete,        MANAGED_BIT | CONTROL_BIT)
+	SETUP_EVENT(MoveCtrlNotify,           MANAGED_BIT | CONTROL_BIT)
 
 	SETUP_EVENT(AllowWeaponTargetCheck,     MANAGED_BIT | CONTROL_BIT)
 	SETUP_EVENT(AllowWeaponTarget,          MANAGED_BIT | CONTROL_BIT)