notes on implementation in docs (#6)

R/anyflights.R

@@ -18,6 +18,13 @@
 #'   airport in a given year and month
 #' }
 #' 
+#' The recommended approach to download data for many stations (airports)
+#' is to supply a vector of stations to the \code{station} argument rather than 
+#' iterating over many calls to \code{anyflights()}. The \code{faa} column
+#' in dataframes outputted by \code{get_airports()} provides the FAA LID
+#' codes for all supported airports. See 
+#' ?\code{\link{get_flights}} for more details on implementation.
+#' 
 #' @param station A character vector giving the origin US airports of interest
 #'  (as the FAA LID airport code).
 #'  

R/get_flights.R

@@ -6,6 +6,12 @@
 #' note that, even with a strong internet connection, this function 
 #' may take several minutes to download relevant data.
 #' 
+#' This function currently downloads data for \emph{all} stations for each month
+#' supplied, and \emph{then} filters out data for relevant stations. Thus, 
+#' the recommended approach to download data for many airports is to supply 
+#' a vector of airport codes to the \code{station} argument rather than 
+#' iterating over many calls to \code{get_flights()}.
+#' 
 #' @inheritParams anyflights 
 #' 
 #' @param ... Currently only used internally.