I've no idea what it would be, but I do know one that isn't.

I just drove by Presidio Lely International Airport (T77) in west
Texas.

It does have a sign, which is how I knew it was an international
airport, a wire fence and a wind sock, but not a whole lot more.
There were two airplanes parked the a Piper Cub and a Piper Colt.

I would have hopped a flight to London or someplace, but no one seemed
to be around the terminal (a trailer house), so I had to continue on
by car. I still did make it an international trip, though, when I waded
across the Rio Grande a few miles down the road.