8. Why Does The Helicarrier Fly And Turn Invisible? - The Avengers
This isn't so much a plot hole so much as simply an annoying problem, but why in the world would S.H.I.E.L.D spend billions of dollars on an aircraft carrier that can fly and turn invisible. First off, there's no practical reason for an aircraft carrier flying, and it makes everything harder on the crew as they have to secure everything on deck before taking off. Secondly, putting an aircraft carrier in the air makes it so much easier to take down as shutting down one or two engines will kill everyone on board in a crash. Also, the way they turn the carrier invisible does absolutely nothing except waste millions if not billions of dollars. Simply reflecting the light from the bottom of the carrier won't make it invisible to radar or to any kind of airborne assault. I guess S.H.I.E.L.D is just the only government organisation that is funded well enough to waste billions of dollars on something they don't need.