I’ve been tinkering with the idea of a hybrid system where the ICE system is its own bolt on component to an electric aircraft that is used for takeoff and altitude before it detaches and returns to the airfield before the aircraft cruiser on electric power. Could even have a rocket launch version for cargo
Separating in flight is a very tricky problem that requires massive amounts of testing and can go very wrong.
They had fuel drop tanks made of paper in WW2.
Cool drones can test and validate the solution without risking a pilot!
You can use some kind of catapult for that
I once saw gliders being launched from a v-8 engine that was mounted on the back of a truck
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