Not for flying (but you could use it for that), I have a Gocycle which is invaluable to me for medical-related reasons – I’m no longer strong enough to cycle up hill.
It is fairly expensive – I think about £1500 new – but I got mine at a reduced price when they sold off some ex-shop demonstrators.
The wheels come off easily for transport; it is not easily or quickly folded beyond that, though it can be done given time.
I have the NiCad batteries. They now do LiPo with a bit nore endurance and slightly lighter, but more costly.
Range of all these things is quoted on level, smooth (no pot holes) tarmac etc. On hills, I squirt the power for a few seconds and pedal for a similar time between, to economise on the battery (and get some exercise). Max speed is about 15 mph.
There are cheaper elec-assisted bikes. For all I know they may work as well but most are heavier – this one has an alloy frame.
In the UK, it is not legal to have an “electric motorbike” (unless specially, and expensively, certified) so it is assistance while pedalling.
Chris N