For film, put it in your carry on. The X-Ray machine can cause the film to become exposed, from my understanding.
As far as taking the car and batteries on the plane with you, I have done this post 9/11. The thing is at going through the scanner you have all these little cylander looking things with wires going between them, they do look like a bomb. One time I we did need to have someone come down from the airline and say it was ok for these to be brought on board, and this was 2000! Most people just ask a lot of questions about the cars, where we race them, how we did, stuff like that. The main things I bring with me on the plane is the car itself and my radio. Everything else I can replace or borrow if they get lost.