one example is Delta:
"After evolving from a fleet of crop-dusting biplanes into one of the nation’s biggest airlines, Delta was in trouble by the mid-2000s. Squeezed by higher fuel prices and disrupters like JetBlue and Southwest, it was forced to file for bankruptcy. But after renegotiating union contracts and expanding its fleet with used planes instead of costly new ones, among other things, Delta once again took flight. In 2013, 120.4 million passengers boarded Delta planes—more than any other airline."