flight fling
The act of sneaking into an airplane bathroom to perform sexual acts with a person who you haven't known for long (and don't plan on knowing them for any longer) while in flight. These acts could be oral, anal, or vaginal penetration.
Man: "Hey hot legs, I need a flight fling."
Woman: "I'll meet you in the bathroom when the seat belt light turns off." ;)
Woman: "I'll meet you in the bathroom when the seat belt light turns off." ;)