I bought a ticket using my friend's credit card.
Did you ask him to use his credit card?
No I just found it and used it without telling him.
It's wrong to use someone's credit card, or anything else, without their permission. You should always ask someone before using one of their possessions, because if you don't then people aren't going to trust you.
WTF did I do anything wrong.
It's not okay to purchase something with someone else's card without asking. It could be a big problem if he thinks it's fraud and has your ticket cancelled. It's always best to ask in that situation.