I would not be inclined to do the change anywhere but on a changing table in the bathroom, but realisitcally, there is not always a changing table in the airplane rest room, then what do people expect a parent to do??
When my DS was 9 months old, we flew from CT to Orlando with him. Southwest had NO changing table in the rest rooms on board. The flight attendant told me that I could NOT change the diaper in the back area on the floor near the bathrooms.

Well what the hell was I supposed to do? Let my child sit in a poopy diaper for 2 hours? I couldn't change him standing up in the restroom because he did not stand up at that point. I was absolutely beside myself about what to do? I was so upset that I was crying (my DS ws not happy about the dirty diaper either, so he started screaming). The plane was totally full, not an empty seat on board. The lady in the seat next to me finally said, "PLEASE, change his diaper on the seat, I'm sure that it is less of an issue than him sitting in a dirty diaper and screaming for two hours for the other people around us". I spread my blanket on my lap and changed my sons diaper. I did NOT want to do it that way, but noone gave me any choice. What the hell else should I have done??????? If the airline doesn't provide a place for changing diapers, what do they expect parents to do??