Originally Posted by The Situation

The rotations through outstations seem to be more reliable, and while these are not bookable flights (without booking two separate one ways which may or may not be financially advantageous), sometimes it is good to be aware of these routes in IRROPs. One of my recent trips, the aircraft goes SEA-xxx-SLC and there is a corresponding aircraft that goes SLC-xxx-SEA. Unless there is IRROPs, that rotation does not change. Unfortunately, that is super annoying for booking a car rental in xxx since the amount of time between arrival and departure is a little longer than the typical turn, so you either have to book the rental car for an extra hour or return it a lot earlier than you wish to arrive at the airport.