Generally speaking it involves any form of anal penetration with the penis.
One can either be the Pilot (giver) or the plane (reciever)
Generally speaking, being the "plane" is a derocitory term used in adolensant hetrosexual males
Use of Brown wings is more commanly reserved to males
Person2: Yeah, but you were the plane!
Person1: No way, pilot all the way, and with a chick!
Similar turn of phrase to when pilots are awarded their wings for flying solo for the first time.
"Congratulations mate, you know have your brown wings"