Remember Air Canada refusing to refund during COVID and actually went challenged US DOT Consent Order requiring AC to refund? Air Canada's argument was US DOT's position on requiring carriers to refund on cancelled/significantly changed flights was not binding.

Master thread Air Canada Refunds vs credits; Class action lawsuit filed

US DOT is about to making it binding - https://www.federalregister.gov/public-inspection/2024-07177/refunds-and-other-consumer-protections
https://www.transportation.gov/briefing-room/biden-harris-administration-announces-final-rule-requiring-automatic-refunds-airline