It is categorically not true that US airlines only received government support in the context of 9/11 and Chapt 11.

Here are some ongoing subsidy programs/protection rackets (h/t sam) that add up to billions too:
- Rural service subsidies
- Military readiness payments to have the option to use planes during wartime (aka free money since govt pays full commercial rates if the handful of times they actually have used the plans)
- Offloading legacy pensions to PBGC - every airline has dumped its retirees on the federal govt - this one make me specially mad as a fairness issue
- Fly America Act for tax payer funded travel
- Restriction on foreign carriers carrying traffic within the US
- Restriction on foreign ownership/ foreigners starting a U.S. airline (Branson had to jump through hoops to start Virgin America - even pre-IPO the most he coulld own was about 20%)
- Anti-trust Immunity for JVs: So we can all get price gouged on TATL flights
- Interest rate subsidies for certain airline debt that gets treated as municipal financing

This is just at the federal level.....