Rhino wrote:I meant inside the building. They can't do a whole lot about the ramp area, though at a commercial airport, usually you are technically within the secure area on the ramp. The FBO needs to post the doors on their buildings, which would mean you'd have to lock the gun in the aircraft before entering. But if you're carrying passengers for hire, you aren't allowed to carry anyway, except under the TSA armed pilots program.
At an airport that has Part 121 (airline service), the ramp surrounding or adjacent to the terminal building is off limits to carrying concealed weapons. The entrance to this ramp is marked on the tarmac and there is signage where there could be foot traffic from other airport ramps. GA has access to KCLE customs at gate A-14 within the restricted area, outside the building. But I can't think of a scenario where you might be carrying to clear customs inbound.