Flight delayed or canceled? What you need to know and what airlines owe travelers.

Sarah Cannon was ready to start her vacation last summer on Hawaii's big island. She, along with her in-laws, her husband and their three kids, was ticketed to fly nonstop from Denver to Kona for about a week in the tropics.

Instead, Cannon and her family got to experience a winding journey that involved mechanical issues, three different airplanes, multiple flight crews, an extra layover in California and a series of incremental delays that ultimately added up to almost 24 hours.

"It was laughable the number of texts and emails I got from United," Cannon said. "We've literally spent thousands of dollars for a direct flight, I should've gone with a cheaper two-stop option."

For her trouble, Cannon said, United Airlines gave her around $30 in meal vouchers per person and a form letter of apology over email.

And that may be all she's going to get because there's no single set of rules for airline travel woes.

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Some rules, like those covering refunds for cancellations and significant flight delays by the airline, are dictated by the U.S. Department of Transportation. Others, like hotel and meal vouchers and expense reimbursement, are up to individual airline policies spelled out in dozens of pages of legalese known as a contract of carriage.

Can I get a refund if my flight is canceled? 

Airlines are required by the DOT to offer a refund when they cancel a flight. It doesn't matter if the reason for the cancellation was outside their control, like weather, or within their control, like maintenance issues or flight crew shortages. And it doesn't matter what kind of ticket you bought, including nonrefundable tickets or basic economy tickets.

Airlines prefer to automatically rebook you on their next available flight, but you are under no obligation to take it. Keep in mind, though, that a refund a) might not be instant and b) probably won't cover the cost of a new last-minute ticket unless your original ticket was pricey. So in many cases, the next-available flight might be the least-expensive option for getting to your destination or back home when things go awry last minute.

If you opt for a refund, you are eligible to get your money back, not just a travel credit or voucher. Airlines are quickest to offer credits and vouchers first, so travelers who want their money back instead often have to take some extra steps. Southwest and Delta, for example, automatically issue travel credit, so travelers who want their money back have to request it.

How do I know what I'm owed? 

The DOT has a traveler-focused dashboard (which you can access by clicking here) to help passengers whose flights are canceled or delayed figure out what they're entitled to. 

In theory, the same DOT rules for cancellations also apply to significant delays, meaning passengers are eligible for a refund regardless of the cause of the airline's delay. The only wrinkle here is that airlines' definitions of "significant delay" vary.

"Whether you are entitled to a refund depends on a lot of factors – such as the length of the delay, the length of the flight, and your particular circumstances," the DOT says.

The rules are different – and more traveler-friendly – in Europe, where laws require airlines to compensate passengers at least 250 euros for delays of three hours or more, and up to 600 euros for longer delays on long-distance flights. Domestic flights in the U.S. have few protections if something goes wrong. For the most part, it's up to individual airlines to decide how to compensate their passengers after a delay.

"There's no specific policy on compensations," said Shaiy Howard, president and CEO of Travel by Shaiy, a travel agency based in South Florida. "Just keep in mind that all airlines vary. When you purchase your airline ticket, in the terms and conditions there can be delays and normally they say you're not entitled to compensation for certain delays like weather."

Airline policies vary widely when it comes to delays, from JetBlue, which has a sliding compensation structure up to $250 in credit per person depending on the type and length of delay, to Spirit Airlines, which does not guarantee any form of delay compensation.Check out this story for a full roundup of airline delay policies.

What if there's a storm brewing or a weather advisory?

Pay attention to your airline's website, mobile app or Facebook and Twitter accounts at the first hint of weather trouble. Airlines routinely issue travel advisories, alerts and waivers (the names vary by carrier) ahead of big weather events, allowing travelers to move their flight to an eligible earlier or later date. You usually won't have to pay a change fee or fare difference if your flight meets the criteria.

Airlines also sometimes proactively cancel flights, so they don't strand passengers and crew during a storm, so check your inbox regularly for updates from the airline about flight changes.

If you're already at the airport when the flight is canceled, check out airline self-service options for rebooking. The snaking line at the customer service counter or gate and the airline's reservations centers aren't the only way to book a new flight. Many airlines allow you to rebook your flight (if they haven't already or you don't like the flight they picked) on their websites and mobile apps.

The airline can't get me on another flight until tomorrow (or later). Do they pay for a hotel? 

Here's where things get trickier and involve those contracts of carriage. Airline policies generally state that they only pay for a hotel if the flight cancellation or overnight delay is their fault, and then only if you don't live in the city you're stranded in. The earlier you request one, the better, as airport hotels sell out quickly when there's flight cancellation mayhem.

Weather, of course, and air traffic control issues are outside of airlines' control, so passengers whose flights are scrubbed for those reasons generally aren't given free hotel stays. (Many airlines do offer discounted hotel rates for those impacted by weather cancellations, so be sure to ask.)

How do you know the reason for your cancellation?

"I think passengers, quite frankly, have a right to be suspicious,'' William McGee told USA TODAY in 2021 when he was an aviation adviser to Consumer Reports. "Airlines are not forthcoming on a lot of issues like this.''

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At the same time, the former airline flight dispatcher says passengers often don't understand how weather across the country can have a ripple effect on an airline.

Savvy travelers should jot down gate announcements or conversations with employees about the reasons for the delay as well as screenshot any alerts sent about the delay via text or the airline's mobile app to plead their case for reimbursement if the airline denies hotel accommodations due to weather.

I can't wait two days for another flight. Can I fly a different airline? 

Stranded passengers are free to check options on other airlines, but whether the airline that canceled the original flight picks up the tab is another question.

Most major airlines, with the notable exception of Southwest, have so-called interline agreements with competitors so they can easily transfer passengers over when they don't have room. But airlines prefer to keep travelers on their flights, so the option isn't usually offered upfront.

Spirit and other budget carriers don't have interline agreements. Spirit's contract of carriage states: "With limited exceptions, Spirit will not reimburse guests for flights that they book on other carriers.''

I'm hungry and airport food is expensive. Will the airline reimburse me for meals?

As with hotel stays, meal vouchers also are generally only doled out when cancellations and long delays are caused by the airline, but it never hurts to ask in any situation. Some airlines, though, including Delta and Southwest, have been known to roll in snack carts or order pizza during extreme weather and other situations outside their control.

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What else should travelers know?

The three biggest pieces of advice some experts offered were to join the airline's frequent flyer program, take the earliest flight out if possible and buy travel insurance.

"I advise all my clients to purchase travel protection," said Howard, from Travel by Shaiy. Even if an airline doesn't compensate you following a delay, travel insurance may reimburse you for expenses like rental cars or hotel rooms that you incur as a result. 

Marc Casto, president of Flight Centre Travel Group, said it's also important to pay attention to which kind of ticket you purchase.

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"At the stage of buying, I would encourage travelers not to buy the cheapest fare. Those are the most likely passengers to get bumped," he said.

Booking through a third party like Expedia or Orbitz can also add a layer of complication if something goes wrong, Howard and Casto said, because airlines usually require passengers to make changes and file complaints through their booking agent, and the websites sometimes have different rules around compensation.

Cannon agreed that she would be more careful about buying travel insurance in the future.

"My 4-year-old said, 'next time can we just take a boat to Hawaii?' " she said. "For the other travelers that are out there, either be flexible or drive, or take a boat as my toddler says."