[Sontagged]

https://www.youtube.com/watch?v=fyAoBI-8Uxg

This theory is everywhere and the only way I can disprove it is by accounting for all the fuel that is supposedly stored in the wings or fuselage of a plane.

(I haven’t had time to watch the link, don’t blame me for whatever is said... I just picked a random one that seemed to account for the white condensation that comes out of the wings... it’s all beyond my pay grade... so again, don’t blame me!)

[NorthMountain]

I am professionally involved in aviation, related to aircraft the size of the DHC-6 Twin Otter. I can personally attest to having personally pumped JET-A and JP-8 into the belly tanks of a Twin Otter. The stuff coming out of the fuel nozzle isn't compressed air. It looks and smelled like kerosene. I'll go so far as to say that it IS kerosene. I can smell the gas coming out of the turbine engines. It's not compressed air. It smells like burnt kerosene. I'll go so far as to say that it IS burnt kerosene. Funny thing ... when we take off, the belly tanks are full. When we land, they're empty. And the engines are HOT. Funny thing ... the only pipes leading out of the tanks go straight into the engines. And shockingly enough, there are no compressed air tanks anywhere on the aircraft.

Draw your own conclusions.

[NorthMountain]

That artificially speeded up guy on your video has no idea what a Auxiliary Power Unit is for. It’s used to START the main engines. After the main engine(s) are started, they compress their own air; that’s what the compressor is for. The APU can be, and often is, turned off.

OBTW, many smaller turbine engine aircraft don’t have an APU. They use a lead-acid electric battery to start one engine, then use the running engine to start the other.