Itβs a very cool idea!
I see some technical issue:
the amount of air you need to pump into the pipe is so much that probably you need a huge fan turning at very high speed. This means as well a huge motor, and if electric, a heavy battery pack.
At the end it will look like an helicopter with a big fan on top a small cabin.
Check the F35 engine system, for 15 seconds of vertical flying it needs a huge, custom build for this purpose, jet engine.
Fan turning at high speed creates a huge noise.
Probably in a small size it would work, like a quadcopter.