Creating an idea and bringing it to reality can happen in less than a year. But improvement of it for achieving better gain and efficiency may take several decades. A good example of this is Engines. In recent years human effort for increasing vehicle engines efficiency is not limited to mechanical improvement. Adding the benefit of some other technologies like electrical motors to engines led us to a new generation of engines called Hybrid.

Like internal combustion engines, I think we can use the power of new high efficient PM motors for improving the efficiency of jet engines.

This idea came to my mind when I was in a flight and the pilot went to approach the destination airport. In all the time the pilot controlled speed and altitude by reducing engine power and air brakes just like a car going downhill on mountain road. A plane in the sky has big potential energy that can be retrieved and used in the next take off. In approach mode the jet engine consumes low energy and due to the speed and altitude of the plane it can be used as a high efficiency wind power generator. This can be done by adding a new coaxial stage to the shaft of the jet engine. Similarly it can be retrofit to jet engines by adding a big fan to them and making the low noise with better efficiency in low altitude motors named Turbo Fan. Due to the flexibility of the PM motor shape, it can be added as a hollow shaft motor with the outside diameter the same as motor intake diameter and length about 30 to 50 centimeters. Such a motor can be thin enough to match the aerodynamic shape of the engine. So it can't affect engine air flow. It only can increase the overall length of the engine and by some design considerations the overall length can be held very close to initial length. Remember that PM motors are very efficient and for airplanes like the Airbus A380 if PM motors are included, they can produce potentially more than 3MW power regardless of battery size and this huge amount of power can be added to the nominal power of Turbo Fan engines. By this method we can have many advantages that I summarize below.

1- Shorter takeoff with less fuel consumption. Because the
PM motors create enough boost for acceleration.
2- In high altitude Turbo Fan engines are efficient and the
PM motors can produce electrical power for different
systems on the plane. A management system can put any
combination of motor/generator for PM systems.
3- When approaching for landing all PM motors go to
generation mode and save the electricity in a battery pack
for next take off.
4- Due to less fuel consumption, fuel tanks can be smaller
and there is space for the battery pack for the PM system.
5- There is no need for equipment for motor start. It can be
done by PM motors.
6- On the ground the electricity is provided by the battery pack
and there is no need for an extra jet engine at the tail of the 
plane.
7- Safer flight due to extra and immediate power reserved
by PM system.
8- Reduced maintenance cost for engines because they work
almost in lower tension.
9- Traditional generators can be removed.
And many more benefits.