Until someone better informed can answer...
I'm a manual chair user, so my 2 cents worth are from hanging around the gate watching.
At least in the USA, you can expect to "gate check" the power scooter. They'll ask if you need an "aisle chair" to get to your seat. If able, walking with a folding cane or some such is much easier than being strapped into a special, narrow wheelchair. Think about the toilet on the plane, as well.
Expect questions about "wet or dry" batteries. Most are dry these days, but make sure. They may need to be disconnected - make sure you know how to do that. Is there a clutch to let it freewheel as they roll it around the ramp and such. Designed to take apart? That may mean loose pieces to worry about.
Above all, arrive early. Connections? You have options of checking the scooter all the way through and relying on airport chairs at the transfer sttaion or getting the scooter back. In either case - don't ticket tight connections. You may be first on, but that usually means last off.