No major U.S. airlines currently provide cash compensation for disrupted flights.

Is there precedent for this type of rule?

In the European Union, where a similar regulation has been in place since 2004, flight cancellations or lengthy delays may give passengers the right to either a refund or a replacement flight, unless caused by “extraordinary circumstances” like severe weather or political unrest. The rule covers all passengers, regardless of nationality, and routes originating within the European Union — even on U.S. carriers. On flights into E.U. countries, the rule applies only to E.U. carriers.

If flights take off late or are canceled less than 14 days before their scheduled departure, passengers may be entitled to up to 600 euros, or about $660. Passengers may also receive compensation if they’re denied boarding. Claims can be filed with air carriers directly or through an online service like Flightright by providing details about the booking and the cause of the delay or cancellation.

If a flight is delayed overnight, passengers in the European Union may also be entitled to reimbursement for expenses like food, ground transportation and accommodation.

In introducing his proposal, Mr. Biden pointed to research showing that the E.U. policy had made a positive impact on air traffic there. A recent study in the journal Transport Policy concluded that European consumer rights regulations had improved service quality by cutting departure delays and boosting airlines’ on-time performance.

When would the policy take effect?

No one knows for sure, but it isn’t likely to be anytime soon.

Mr. Biden said he hoped the Department of Transportation would “move as quickly as it can to put this new rule in place,” but did not specify a timeline.