Who is considered part of the field of transportation and can pay for TSA’s vetting services through user fees?

According to fee statute (6 U.S.C. 469(a)), the field of transportation includes any individual, activity, entity, facility, owner or operator that is subject to regulation by TSA, the Department of Transportation or the U.S. Coast Guard. This also includes individuals applying for trusted traveler programs, such as TSA PreCheck®.