Flight cancellations and delays are inconveniences at best, and trip ruiners at worst. The good news is, you may have the right to receive some money for being waylaid in an airport for hours on end.

Under European law, if you're traveling to, from or within Europe, you may be entitled to compensation for significant flight delays — when they are the airline's fault. 

"You have a lot of rights as an American passenger when your flight gets delayed or canceled either to, from or within Europe," Scott Keyes, founder of flight deals site Going.com, told CBS MoneyWatch. "That stands in stark contrast to your rights when your flight gets delayed in the U.S."

European legislation EC 261 protects passengers and entitles them to monetary compensation of up to roughly $700 in the following scenarios: 

• Your flight on any airline departed from the EU and arrived at its final destination with a delay of three or more hours.
• Your flight on a European airline took off from outside the EU and landed within the EU, and arrived at your final destination with a delay of at least three hours. For example, an AirFrance flight from New York to Madrid would qualify. 
  

Under both scenarios, you must also have checked in for your flight on time to be entitled to compensation. 

Beyond their control

There are times, however, when your flight may meet these criteria, but airlines aren't required to shell out. 

If the flight delay is caused by "extraordinary circumstances," such as political unrest, extreme weather conditions, terrorist acts and more, airlines are off the hook. 

Incidents like staff strikes, however, are the responsibility of the airline. 

How much money can I get?

The amount of money you're entitled to relates to the duration of the flight, not the cost of the ticket. 

On short-haul trips 1,500-kilometers (or 932 miles) long or less, passengers can earn up to 250 euros. On mid-distance flights, the maximum compensation is 400 euros. Passengers are entitled to 600 euros on long-haul trips.

How do I claim compensation?

Customers can contact the airline directly, but this can be cumbersome and time-consuming. Airlines often attempt to wear passengers down in hopes that they'll give up on the claim, according to experts. 

"In practice when you go to an airline directly and try to get the compensation, it becomes very hard to navigate their customer assistance, or a lot of times you can't call," Eric Napoli, vice president of legal strategy for AirHelp, a company that helps passengers claim compensation. "It's incredibly difficult for you to figure out where to send your claim, who to claim it with. Generally people don't have access to information about why their flight was delayed so you have to trust the airline."

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It isn't cost-effective for passengers to retain lawyers, either. 

"That's why claim companies like FlightRight exist. We enforce your rights against the airlines, because it isn't affordable to go to a lawyer to claim 250 Euros," said Claudia Brosche, legal counsel at Flightright, another airline claims firm. 

Typically, if these services are successful in claiming compensation, they'll keep a percentage of the payout. If they're unsuccessful, passengers don't owe anything.

For example, AirHelp recently denied a claim for compensation for a flight from Milan to New York that was delayed by more than three hours. The service determined the delay was related to a passenger medical emergency, which is considered to be out of the airline's control. The inquiry was free, however. 

"Airlines bank on the fact that passengers don't know rights, and that the longer it takes and the more documents they ask for from you, the more likely it is that you'll lose interest," Napoli said.

Keyes of Going said he's successfully filed claims directly with airlines that were quickly accepted. "The filing of the form was relatively straightforward and I never had to fight with the airline," he said. 

However, it took roughly eight months from the time he filed his claim until he received his compensation check in the mail. 

"It was processing time that caused the delay, it wasn't back and forth with the airline trying to fight for my rights or convince them I was owed this," he said. "It was, 'yes, you're owed compensation, it might take a little while for the check to show up.' And that certainly held true."