I'm up to 44: only missing Alaska, Hawaii, Montana, Arkansas, Louisiana, and Maine. (Yes, I know, I live so close to Maine I should just go there.) There are no states that I've only been in an airport, but there have been a couple of states (Mississippi, Wyoming, South Dakota, Kansas) where I drove into them, picked up a map, took a picture, and/or had a meal, and drove back out an hour or two later.