Days of long tarmac delays may be over, new numbers suggest

— -- The days of being stuck for hours on a plane on an airport's tarmac appear to be over.

Between January and June, only four planes carrying passengers on flights within the U.S. sat for longer than three hours, the Transportation Department reported Thursday.

That compares with 35 tarmac delays for domestic flights during the same period last year, which was the first full year that a new government rule preventing long tarmac delays took effect.

The government imposed limits on them in April 2010 after a series of incidents in which passengers were stranded on planes for more than 10 hours. In the first six months of 2009, for instance, there were 586 tarmac delays of more than three hours.

The rule on domestic flights requires airlines to let passengers off a plane if they have been waiting on a tarmac for more than three hours. Exceptions are made only if the delay is for safety, security or air traffic control-related reasons.

Carriers face steep fines if they break the rule — up to $27,500 per passenger. So far, only one airline has had to pay up. Last year, the Department fined American Eagle, the regional unit of American Airlines, $900,000 for lengthy tarmac delays at Chicago O'Hare International Airport in May 2011.

"Our new airline consumer rules and our vigorous oversight of the aviation industry are holding airlines accountable to their customers," Transportation Secretary Ray LaHood said in a statement accompanying the release of the numbers. "We will continue to help make air travel as hassle-free as possible."

Since August 2011, the tarmac delay rule has also applied to U.S. and foreign airlines operating international flights at U.S. airports. The limit in those cases is four hours, however. In June, there was just one long tarmac delay on an international flight.

Airlines opposed the rule, arguing that it would force them to cancel more flights. And while it hasn't eliminated all but the longest of delays passengers may have on a tarmac, some analysts say it may have prompted airlines to cancel more flights rather than face the steep penalties.

"The … 'three-hour rule' very quickly becomes a 90-minute rule in actual decision-making practice, which indisputably causes more pre-emptive cancellations than otherwise would be the case," says Robert Mann, president of R.W. Mann and Co., which provides industry analysis.

The Department has instituted a number of other new consumer protections in recent years, including a requirement that airlines post on their websites the on-time performance of their flights.

Data released Thursday by the Department's Bureau of Transportation Statistics also showed that carriers are continuing a streak of getting passengers and their luggage to their destinations on time.

The 15 largest U.S. airlines were on time 83.7% of the time during the first six months of this year, the highest for any comparable period in the 18 years the department has been collecting data. The previous high of 82.8% had been set in 2003.

Airlines also canceled the fewest flights in the past 18 years. The 1.1% cancellation rate for the six-month period bested the previous record of 1.3% in 2002.