Smallest airports that I've flown into/out of:
- EWB [New Bedford] on Provincetown-Boston Airline (PBA)
- MHK [Manhattan Kansas] on Capitol Airlines (CPX) - the airline's home airport.
CPX was notorious for counting the passenger reservations for their flights. If they didn't have at least a certain number, the equipment would mysteriously develop a problem and the flight would be cancelled. They would also every once in a while get shut down by the FAA for safety issues - such as having someone (I think it was a child) sitting in the aisle during a flight.
- MSV [Sullivan County International Airport] in White Lake, N.Y. in the Catskills near Monticello (hence the "M" in the airport code).. I just drove up to the front door of the terminal and parked next to it. Left the car there until I flew back a few days later. I don't recall which airline I flew, just that I had a connecting flight in LGA. I never found an "international" flight to/from there. I expect that part of the name was just to give it a more impressive name.
- RPN [Rosh Pinah] on Arkia (IZ)
- SIT [Sitka Alaska] on Alaska (AS)