The government has introduced a new airline rule aimed at protecting passengers from getting stuck on runways during long delays.
The regulation prevents planes from sitting on the tarmac for more than three hours without allowing passengers to exit.
"Passengers on flights delayed on the tarmac have a right to know they will not be held aboard a plane indefinitely," Transportation Secretary Ray LaHood said in a statement. "This is an important consumer protection, and we believe it should take effect as planned."
The rule, which started April 29, also requires passengers be given food and water after two hours and the airline must provide a working toilet.
Airlines that break the rule can be fined up to $27,500 per passenger for each violation.
Delta, American Airlines, US Airways, JetBlue and Continental Airlines all requested exemptions from the rule for operations at busier airports like New York's JFH and Philadelphia International Airport. All were denied.