Hand check is the best method to protect your film and carry it in your carry-on bag. I have sent my entire camera bag through the security checkpoint machines and had no problems with the lead boxes or lead bags in some instances; in others, I have been asked to open the bag for a search. Much easier if you just take your film out of the plastic containers, put the film rolls in a clear ziplock type bag and when you approach the security checkpoint, remover the ziplock bag and place it in a tray along with car keys, change, etc. or ask for a hand check. WARNING: The newer x-ray machines use to check checked baggage have a variable intensity function so that if the machine detects something that it cannot penetrate (i.e lead bag), it dials up the energy level until it can penetrate the material. This has and will cause damage to exposed and unexposed film. To be safe, HAND CHECK!