It's unlikely it was caused by the airport scan...(there some level of radiation but i don't think it can broke the drive)
if u ask what can be cause... the one i can think of that cause flash disk to broke...
- Low quality parts or manufacturing defect (i will break sooner)
- Electrical short..
- Rough treatment (physical damage)
- high temp (this not noticeable, it reduce the reliability over time)