FWIW Allegiant used to never fly on Tue/Sat and less flying on Wed than the other days. Especially in smaller bases. My last few years there that evened out a bit. Allegiant is mostly a leisure airline and nobody leaves on vacation mid week or Saturday. Mostly leave Thu/Fri and come home Sun/Mon. It was nice knowing you were unlikely to work those days and could plan things well ahead. As it turned out since there were very few flights working the low days trended very senior. Picking up a reserve shift on a Tuesday or Saturday was easy money (yes line holders can do that at G4).

I think the problem with Spirit and Frontier is that they fly to large airports and try to compete with the legacies offering a much lower fare to the same places. The legacies squashed that by offering cheap basic fares with better service and more reliability. If you live in Iowa or Wisconsin or upstate NY and want to go somewhere Allegiant is alone offering direct flights to airports most other airlines either don't serve direct (like Destin or SW FL or Myrtle or Nashville) or serve with connections that usually involve an RJ and then a drive to the final destination. If you live in Chicago or Dallas or Atlanta you have lots of better choices than any ULCC. The other ULCCs would be wise to copy the allegiant model and quit operating in major airline hubs. Small airport point to point is the secret of Allegiant's success but that's a huge culture change from what most airline pilots are used to. Working at allegiant was a true part time job and definitely a slow paced lifestyle compared to other airlines. That's probably why allegiant pilots seem to be less militant and other than low pay and a crappy in house PBS system that abrogates seniority don't have many complaints. The other down side to that lifestyle is a lot of small bases that you have to actually live in. Very very few G4 pilots commute.