The funniest conspiracy theory I've ever heard is that airplanes aren't real. Planes are really just big, huge super hybrid prehistoric birds with helmets on that have 2 inflatable balloons that look like jet engines. They have speakers mounted to their helmets (that look like the nose of an aircraft) which emit a loud, engine-like noise. On the ground, when you enter a terminal and go into a airplane, the cabin fills with a anesthetic gas and it loaded onto the back of a truck and driven to the location while a projector plays footage that was captured by one of the birds of the clouds and overview of the grand. But because you're half-lit on gas, you don't realize this and this is why we have "jet-lag."
Multi-Trillion dollar industry, the flight travel industry, is a total fleece, big bird propaganda.