If you remember physics class, MV = MV. So the
mass of air X the speed of air being pushed = mass of the airplane X the speed of the airplane.
So since air is very light, you have to push a lot of air and in very high speed. It is very difficult to find FAN that can blow that much air.
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I used to take flight lesson. When a plane is ready to take off, I could be 10 cars away, and I can feel a huge wind blow (almost enough to off balance me as I'm walking). That is a lot of moving air.
Good Luck...