Your flight got cancelled and you want to know what your rights are. The honest answer is shorter than the airline's hold music makes it sound. If a US carrier cancels your flight, or changes it so much that it isn't really the flight you bought, you are owed your money back. Cash, to the card you paid with. Not a voucher, not a credit, not travel money that expires in a year. That right holds whether the cancellation was the airline's fault or the weather's.
Flight cancelled: what are your rights, exactly?
Two separate things are on the table. The first is a refund. If the airline cancels and you don't want the seat it offers instead, you can decline the rebooking and get a full cash refund, including the taxes and bag fees you paid. The second is the rebooking itself: if you'd rather just get where you're going, the airline will put you on the next flight it can, usually at no extra charge. You pick one. You do not have to take the first thing the gate agent pushes.
A voucher is where airlines like to steer you, because a voucher keeps your money inside the airline. You can say no. Ask for the refund in plain words, and don't accept "we can only offer a credit" as the end of the conversation.
What to ask for at the gate, and what to save
In the moment, the smart move is to get rebooked fast and sort the money out later. Ask to be put on the next available flight, including on a partner airline if yours has nothing good. If the cancellation is the airline's own fault, you may also get meals or a hotel, though a rule change this fall narrowed which causes count as the airline's fault, so fewer disruptions qualify for those extras now than did a year ago. Treat anything past the refund as a bonus, not a promise.
Then save everything: the original confirmation, the rebooking details, and receipts for any hotel or meal you paid for yourself. A refund you can prove you're owed is a lot easier to collect than one you half-remember. If your trip touches the EU, departing from an EU airport or flying home on an EU carrier, you fall under a separate and stronger set of rules that can include fixed cash compensation on top of the refund. That one is worth its own look.
Why a deal email is telling you this
We send flight deals, not claims services, so there's nothing here we're selling you. We mention it because the instinct is the same one we lean on everywhere: keep your own money where you can reach it. It's the reason a refundable ticket rarely earns its markup, and the reason the 24-hour cancellation rule is such a quiet gift. When the morning email points you at a fare worth booking, book it knowing that if the airline bails, the money is yours to get back.