Flew from LGA to JFK due to equipment failure warning light right after take off on AA in mid-2000s. Of course a fully fueled plan is too heavy to land back on LGA's short runways.
Best part was after we landed, FA gave the usual spiel, with a twist:
"Ladies and gentlemen, welcome to New York's John F Kennedy Airport, where the local time is _____. We thank you for flying American Airlines, and for future reference, I'd like to remind you that the quickest way to get from La Guardia to JFK is via a yellow taxi cab".