We went to Las Vegas this weekend for a wedding and flew out of O'hare.(We usually fly out of Midway) We got there 2 hours and 15 minutes early for an 8:30 a.m. flight. There was nobody there. Soooooo I asked the gentleman (who was quite chatty) about film. He told me "DON'T PUT ANY UNDEVELOPED FILM IN NON-CARRY-ON LUGGAGE, IT WILL BE RUINED"!! I know there have been many posts about this but it never seemed be be answered for sure. He told me the speed doesn't matter.