Ranking of most denied boardings.
1. ExpressJet
2. JetBlue
3. Skywest
4. SWA
5. AA
6. Frontier
7. UAL
And that free ticket or credit in travel doesn't get you nearly as much on ExpressJet, JetBlue, SkyWest, Frontier, or even SWA compared to the big three.
The only time anyone in my family was bumped was by Delta on a trip to France (with a layover in NY?), wife arrived in plenty of time, checked in at the ticket counter, checked bags, was told boarding was at X:XX, went through TSA, bought a water arrived 15 minutes prior to boarding was supposed to start only to be told seat was given to another because she wasn't there in time and plane had already boarded, she tried to tell them she was there prior to time on the ticket, was promptly brushed aside told to call the 800 number, she found another gate agent at a flight that had already left, he looked at the ticked, looked at the computer, looked at her said "oh...." he made a phone call and in minutes she was re-booked on a direct flight, she arrived before her original flight. The first gate agent was a b***h, but the second was very professional.