Film damaged by X-Ray has happened to me, it can happen to you. It probably won't. But it might.
Here is the straight story:
Please read this:
The security at US airports has improved measureably from the year or two after 9/11. The agents have actually been trained, and know what traveler's rights are.
How you conduct yourself has direct bearing on how your film will be handled. Go through security early enough that a hand inspection will not hinder you. Pack simply. Think it out ahead of time.
How you deal with You will declare the film when you get home. Customs is your business.
You may also order film from B&H, and have it sent to you.
"This suspense is terrible ! I hope it lasts."