User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-5043481-20121102124845/@comment-5043481-20121104213845

Maybe it creates a huge voltage between its top fins and bottom fins. To equal the charge, the air is ionised and the ionised gas moves downwards.

I believe a smaller and similar device was actually constructed, and was featured on mythbusters as an antigravity device. It was busted, as it generated thrust, but it still flew.