First you must whisper to someone a countdown until you take off (it's 
very important do take off at the same time). If your gears are close 
enough to each other for a trade, do it. Keep it until you warped. 
Because you can't warp while you trade you will remain in the map. Be
careful though if you land you can't take off again and if you use the
warp from the first map -> city you will land and go in the city.
Be careful that you might be banned if you fly in the town.