Climbing to altitude is the straightforward part. The transition from zero knots to the stall speed of the aircraft (minimum speed at which it can remain airbor

Climbing to altitude is the straightforward part. The transition from zero knots to the stall speed of the aircraft (minimum speed at which it can remain airborne) is the tricky bit. Designing for a lower stall speed necessitates wings which produce higher drag (by being larger) which requires more propulsion, which means bigger batteries and motors. So launching from a catapult or rocket or mothership or whatever means a lighter plane.