Cheap oil does benefit everyone. And that’s the point. An environment where everyone can take advantage of the tailwind is not what the ULCC model was built for. That “fit fleet” of young, fuel efficient planes is meant to take advantage of the competition having to pay more for their oil and their older aircraft.

Fuel is the number one expense for any airline. The legacies can play their games to suppress the ULCC niche and it’s growth when that cost is low. Those opportunities are much more limited when oil is selling for a more traditional price point.

This isn’t rocket science. The cost structure and higher personnel and support costs of the legacies make competition with a ULCC nearly untenable when oil costs more.