The first one is supposed to look like a stick figure jacking off. If you look at it with the O at the top and the G at the bottom, you can clearly make out where the penis and hand are.
There's a face just below the stairs, a girl behind the stairs with glowing eyes, and a face engraved into the wall on the lower left. I didn't really find them that creepy. :/
I know the AC-130 Hercules doesn't have turbojet's, I saw enough of them flying overhead when I was in Yokohama. But I don't think that plane in the foreground is an AC-130.