The number of flights that delayed passengers aboard planes for at least three hours doubled last year, prompting the Transportation Department's office of inspector general to recommend regulators more aggressively monitor airlines' online plans and record-keeping.
The report, filed Thursday, says guidelines for passenger comfort -- providing food and water within two hours, comfortable onboard temperatures, notifications and lavatory service on delays of three hours or more -- have not been followed, and when passengers complained, the DOT often took the airline's word about what happened without seeking other evidence.
The audit also said the DOT needs to push airlines to more clearly communicate to passengers their rights during a long onboard delay, mainly by using their websites to spell out the guidelines.
"While lengthy on-board delays are rare events, they cause passengers undue discomfort and inconvenience, particularly when the delay occurs on the tarmac with passengers on board the aircraft," the report says.
Among the reasons for the passenger protections was a snow and ice storm on Valentine's Day 2007, when 10 JetBlue Airways flights -- and hundreds of passengers -- were stuck on the tarmac at Kennedy Airport for up to 10 hours.
That episode and a series of similar long, onboard delays nationwide led the DOT to implement a rule that on domestic flights passengers must be allowed to get off the plane if they've been delayed on the tarmac for more than three hours, or four hours for international flights.
Airlines that break the time-limit rules can be fined up to $27,500 per passenger. As of April, the DOT had issued more than $3.5 million in civil fines, the report said.
Those fines may have helped -- the number of long, onboard domestic flight delays plummeted from 868 in 2009 to 42 in 2012, according to the Bureau of Transportation Statistics. But in 2013 it jumped to 84. From January to August 2014, there were 18 domestic long, onboard flight delays and three on international flights.
"Passengers have a basic right to food, water and tolerable conditions when faced with excruciating tarmac delays," Joe Sitt, chairman of the New York City travelers advocacy group Global Gateway Alliance, said in a statement. "This report makes clear the federal government hasn't ensured that those rights are easily and publicly accessible to passengers, or provided enough oversight of whether airlines are following these rules."