I have masturbated in airplane bathrooms many times.
The first time was when I was about 13. I had just learned the pleasures of masturbating and was doing it 2-3 times a day. When we got on the flight I wanted the aisle seat so I could get up and walk about the aircraft in flight. I recall watching myself in the mirror and not having much pubic hair on my tiny pink penis. From that flight on I always try to cum on an airline flight, even a short commuter trip.
Two weeks ago I was on an overnight flight to Milan and I tried to masturbate in the cabin instead of going to the bathroom. I was in a window seat and there was nobody in the seats beside me or in the center row until the other side of the airplane.
I waited until most other passengers were sleeping.
At first I just rubbed my cock through my pants but I then pulled a blanket over my tray-table holding it in place with my laptop computer. This created a 'tent' that covered me and I was able to pull my pants down and really stroke my penis fully.
The problem was I did not have any lube and I can't cum without it.
On the flight back I was better prepared. I had stopped off at a drug store and bought some condoms and three of the little tubes of single use lube. I also wore a pair of lose fitting cargo shorts.
This time I had a person in the seat beside me so soon after we were in the air, I just went to the bathroom and jerked-off using the lube.
After dinner was served the guy beside me moved back a few rows and I again had the row to myself but there was a family with children in the center seats on the other side of the aisle.
I waited until everybody was sleeping or watching the movie and set my tent up again. Pulling down my shorts almost to my knees I was able to put some lube into a condom and slide it over my cock.
I sat at a slight angle on the seat, turned to face the window with my back to the main cabin. This was I was able to hook my leg into the seatback pocket and comfortably hold my now hard penis out horizontally from my body.
The feeling was fantastic as I slid the well lubed condom up and down the shaft of my penis slowly at first but faster as I came closer to coming.
When I came I held the condom back against my balls and it easily caught all the semen without making a mess although my hand and cock were all slimy.
After a moment I removed the condom and stuffed it, wrapper and the lube tube into a soda can and left it in the seat pocket. Pulling up my shorts, I wiped my hands and cock off on the blanket, neatly folded it and returned it the overhead bin for the next passenger to enjoy.
I managed to sleep for a few hours and found the time and energy to jerk-off a third time in the bathroom shortly before we landed.