I very much appreciate the question and the answers on the origination of planefagging. Here was my recent-convert take on it the other day:

...planefagging, a term which implies zero disrespect to the beloved fags among us, but simply describes watching and reporting the movement of planes with a flamboyantly disregard for the disapproving squeals of squares who have no tolerance for this kind of “deviant”, obsessive activity.