Airline passengers may have been unfairly treated while European Union’s regulators raced to approve bailouts to struggling carriers, the EU’s financial watchdog warned.

The European Court of Auditors said Wednesday it has started to assess whether the European Commission protected the rights of citizens who traveled by plane or booked flights during the coronavirus crisis.

“In times of Covid-19, the EU and member states have had to strike a balance between preserving air passenger rights and supporting the ailing airlines,” said Annemie Turtelboom, the ECA member leading the audit. “Our audit will check that the rights of millions of air travelers in the EU were not collateral damage in the fight to save struggling airlines.”

Airlines balked at issuing refunds last year as pandemic restrictions grounded plans and racked up $150 billion in losses for the industry. That saw them clash with EU rules that require airlines to compensate passengers for canceled flights. The U.K. competition regulator is investigating if carriers ignored consumer rights by refusing refunds.

The commission’s press office didn’t immediately respond to a request for comment.