If you're in the mood to miss your flight out of Bozeman or sit around the gate area for an extra 45 minutes before your flight - ask a local what time you should show up at the airport. There's a very decent chance they'll give you crappy, non-detailed, and not particularly accurate advice.
You've noticed this one too, I bet. Under normal circumstances, I travel a lot. Always have. Bozeman's airport has for some reason always been one of my local happy places because I was either leaving on an adventure of returning to the home I love.