This should give an idea of why they didn't find the engines at the pentagon: http://au.youtube.com/watch?v=WMyPC5wVvbs
Smaller scale, but you get the idea. The Phant,m is no light weight though, and as you can see, two gas turbines being oblitorated.
A Gas Turbine is not an engine similar to a piston engine. It's not a big solid lump of cast iron. It's a comparatively thin tube with a shaft up the middle, attached to which is a couple of hundred blades, all happy and willing to go everywhere at a moments notice. I consider this to be a good explaination as to why they didn't find the donks as lets face it, the pentagon is just a bunch of walls.
As for the pilots skill level. The bigger it is, the easier it is to fly. If i can land one of these puppy's in a simulator, I'm sure someone on a mission, with some formal training, shouting "Allah Akbar" could pull off anything you want. Hell, give me a couple of hours in the Sim, and I'd give it a shot.
Oh, and I noticed you got really interested again when somebody agreed with you. Way to hold a balanced discussion.