Before you accept that flight credit after the ground stop, read this: Rebooking could cost you your refund

Thousands of passengers were left reeling from cancellations and delays as a result of the FAA's nationwide ground stop on 13th November. Airlines had travel waivers in place to allow affected customers to change their plans without incurring certain fees.

But taking up the flight credit or rebooking straight away may not necessarily be the best option. If your flight has been cancelled, you may in fact be entitled to a full refund. The order in which you do things is important.

Why should you think twice before accepting flight credit?

The FAA ground stop was due to a telecom failure at the ATC centres. As it was outside the airlines' control, US carriers are normally not obliged to provide hotel accommodation, meal vouchers or cash for the delays.

However, that doesn't mean passengers lose their right to a refund.

Under DOT rules, customers are entitled to a full refund if an airline cancels their flight or makes a material change and they subsequently decide not to travel. The refund is due irrespective of the reason for the cancellation.

It must include the ticket price, taxes and any additional fees (e.g. baggage and seat fees). The airline must refund the money to the original method of payment within 7 business days in the case of a credit card and within 20 calendar days in all other cases.

PIRG have advised the affected passengers to get in touch with their airlines and ask for a refund rather than just accepting the voucher.

Teresa Murray from PIRG explained the rule very clearly: “It doesn’t matter why the flight is cancelled."

When does rebooking turn into a credit instead?

The key difference is who cancels the booking. If the airline cancels your flight or alters its schedule substantially, then you can reject the alternative and get a refund. If, however, you cancel your own booking under an airline's travel waiver prior to the airline cancelling it, then you may be entitled to a credit rather than a refund.

TheTravel report says Delta's waiver could turn a cancelled trip into an eCredit, while Alaska passengers could get the money into their Alaska Wallet or as a credit certificate.

Consumer advocates quoted by FOX 5 were advising the stranded passengers to just wait for the airline to cancel the flight before they made a decision. That could, in effect, be a way of avoiding the situation where they give up a refund they're absolutely entitled to.

What did the airlines offer following the FAA ground stop?

The travel waivers that the major carriers have announced all come with different conditions. As per KPRC 2, United allowed affected passengers to rebook without change fees or fare differences as long as the new flight departed by Nov 20, was in the same cabin and was the same route.

Delta have allowed customers booked for 13th/14th November to change their travel without charge up to 21st November, according to TheTravel. American, Southwest, Alaska, Hawaiian and Frontier have all announced waivers of their own with respect to date restrictions. Frontier's waiver still includes fare differences.

Know your refund rights before making a decision. Passengers who have already received a cancellation notice should check whether their refund has in fact been processed. If they have paid for a hotel or meals as a result of the disruption, they can request reimbursement from the airline, though it is not necessary for the airline to reimburse them for those costs in the case of an ATC failure.

Keep your receipts and screenshots of your flight updates. Check whether your credit card has trip delay cover.

The FAA ground stop may have messed up your travel plans, but it didn't remove the federal refund protection. Before you go and accept a voucher or cancel your own booking, make sure you know exactly what you're entitled to.