Can enough motors generate the current to turn a separate one?
What you are looking for has been known for a long time - it's called a perpetual motion machine. 

If it were possible, you could do the following: 

1) Take a 12 volt, 2 amp power source, and connect it to your desired motor and generator. Just as a start, let's say that the generator will put out 12 volts at 4 amps.

2) Connect the generator to 2 motors.

3) Connect the 2 motors to 2 generators each, or 4 generators.

4) Continue the process until you have megawatts of power being generated (16 generations) or gigawatts (another 20 or so after that).

5) At some point connect one of the generators back to the original motor and turn off the power supply.

Do you see the problem? 

If you use a motor/generator with a gain of 1.5 (12 volts and 3 amps) it takes more layers to get to a specific power, but the principle remains the same. Any motor/generator which puts out more power than is put in is impossible under the current understanding of how the universe works. So your electric airplane has the energy stored in the battery at takeoff. And no more.