On the aircraft carrier, just before Doolittle's Raiders take off to bomb Tokyo, you can see someone in a white hat doing something in the cockpit of Colonol Doolittle's B-25. It was probably an advisor of some sort, but looked very out of place. They should have edited it out before the movie was released.
He's right guys. I watched the 2nd dvd with all the bonus material, and at one point there was a guy with a white hat in that bomber, giving some sort of instructions.