We have actually put background pictures of the sky or the golden gate bridge behind the model and it looks like a real airplane flying around. That's pretty neat. That's pretty neat. Obviously there are more models than actual airplanes, and I would guess probably 1 in 2000 actually are constructed. As far as airplanes go, so few are built today that if airplane that you worked on was built you would be VERY lucky.
Most designers never see any of their designs built.
The moderator wanted me to mention something about physics. Actually I forgot, I do use that an awful lot. It is such an integral part of my job that I don't even notice it anymore. Much of the airplane design relies on calculation of forces and moments, and balancing of these things so that the aircraft flys the way you think it should. Very good question.