TSA officials can levy civil penalties — fines of up to $14,950 for repeat violations — and agency officials weigh factors such as whether the firearm was loaded.

It can be suspicious if travelers are dressed for weather that does not align with either location — leading to a potential red flag from TSA. Another “common” behavior that could flag security personnel is when people are seen yawning excessively.

Jeff Price, an airport security coordinator-trainer and a professor of aviation management at the Metropolitan State University of Denver in Colorado, has an extensive background in airport ...