I have not flown with 35mm in a few years.. but what I used to do was have all of my rolls in a clear ziploc plastic bag, and I take my camera body out at the X-ray to send my bags through. Half the time, the agent would ask me to press the shutter on my camera to prove it’s a ‘real’ camera - the rest of the time, they just say ‘cool camera!’ and let me get on with my day.