The are a lot more recent examples of the DOT using this power than there are of the FTC using its Section 5 authority, like the #TarmacDelayRule. But as Robert Kuttner writes, the airlines reneged on their end of the $54b bailout, slashing staffing levels and failing to invest in IT modernization - examples of the "unfair and deceptive" practices that the DOT could intervene to prevent:

https://prospect.org/infrastructure/transportation/ftc-noncompete-airline-flight-cancellation-buttigieg/

18/

The FTC Banned an Unfair Practice. The Department of Transportation Can, Too.

DOT has the same statutory language to effectively ban deceptive flight cancellations, the way the FTC has banned noncompete agreements.

The American Prospect