Thousands of passengers on non-stop flights from Europe to the U.S. over the past month have found themselves with an unexpected stop - an unplanned landing to take on more fuel.
Pilots have had to put down in Canada or elsewhere to top off their tanks, after running into record headwinds which have slowed the flights, using up more fuel than expected.
This story was first reported by the Wall Street Journal which said Continental Airlines has had the most problems. The airline, which has merged with United to form the world's largest carrier, had nearly 60 diversions for fuel on flights from Europe since early December. The airline confirmed the number to ABC News.
Airlines are required to carry enough fuel to reach their destination, and an extra amount in order to land at an alternate airport if necessary.
It's not just the headwinds that are to blame. Continental has switched to smaller twin-engine Boeing 757's on these routes to save money, and those planes can't travel as far or hold as much fuel as wide body planes. The Wall Street Journal notes that that's not a problem if winds are calm, but strong headwinds can cause havoc with schedules.
United/Continental spokesperson Megan McCarthy told ABC News that the headwinds have been a "once in 10 year extreme." McCarthy said the headwinds in December usually average 35 mph. This past December they've hit 54 mph, and on the worst days have been up to 69 mph - twice as strong as usual.
McCarthy noted that most of their 757 flights from Europe - 97 percent of them - did not have to divert. Diversions for fuel, or any reason, are a headache for customers, and cost airlines money. McCarthy said, "We are looking at it very closely, it is an inconvenience to our customers, to determine if there are other options."
The Federal Aviation Administration is also checking to make sure there are no safety issues. In a statement, the agency said, "The FAA is aware that United Airlines aircraft have made more unscheduled fuel stops this year than last year and we are looking into the issue."
USAirways and American Airlines also fly 757's across the Atlantic, but they've had only a few diversions due to the winds. According to the Wall Street Journal, Delta Airlines has had none.
There have been allegations in the past that both Continental and USAirways had skimped on fuel, as fuel costs have skyrocketed. Both airlines denied the charges, and no safety fines were levied.