(Reuters) - U.S. airlines were back in operation on Monday after a series of system-wide outages delayed flights and fired-up customer complaints on social media.
The Federal Aviation Administration said the problem was caused by the Aerodata airplane planning weight and balance program.
The agency issued a statement around 8.30 a.m. ET, saying the issue had been resolved.
American Airlines, Southwest Airlines and Delta Air Lines reported system-wide outages, with United Airlines saying it was unable to create paperwork for some time.
RELATED: 9 best airlines in America
9 best airlines in America
9 best airlines in America
9. Hawaiian Airlines
Previous rank: 8
Why it's here: Hawaiian finished last on the TPG list. The Honolulu-based airline's premium ticket prices and Hawaii-centric route network fell victim to TPG new metrics which increased focus on airfare and network size.
Previous rank: 4
Why it's here: JetBlue suffered the most significant drop in this year's rankings. The New York-based airline struggled with on-time arrivals, baggage and change fees as well as customer satisfaction. JetBlue's position as a boutique carrier hurts it rankings with respect to the size of its route network as well as the lavishness of its frequent flyer program.
7. Spirit Airlines
Previous rank: 10
Why it's here: Spirit jumped three spots in the rankings due to its improvement in areas such as the number of lost baggage while also benefiting from the missteps of its rivals and the merger of Alaska and Virgin America.
Previous rank: 5
Why it's here: American Airlines didn't make many moves apart from a one spot from after the Virgin/Alaska merger. The airline struggled with on-time arrivals, fees, lost baggage, and customer satisfaction.
5. Frontier Airlines
Previous rank: 9
Why it's here: Frontier Airlines made a surprising jump up the rankings. The ultra-low-cost carrier benefitted from its route expansion and its improvement in baggage handling.
4. United Airlines
Previous rank: 2
Why it's here: United Airlines rocky 2017 caused it to fall two spots, but not for the reasons you'd expect. United saw marked improvement in operational effectiveness with the number customer complaints down 17% while also decreasing the number of people involuntarily bumped from flights. However, the airline couldn't keep up with its rivals in areas such as airfare and the quality of its airport lounges.
3. Delta Air Lines
Previous rank: 7
Why it's here: Delta made big strides in airfare, the involuntary bumps, and its frequent flyer program while maintaining its high rankings in on-time performance, lost baggage, and the size of its route network.
2. Southwest Airlines
Previous rank: 6
Why it's here: Southwest improved four spots over the past year thanks to lower airfare and the expansion of its sizable route network. The airline's stellar customer satisfaction score and its free checked baggage policy also helped.
1. Alaska Airlines
Previous rank: 1
Why it's here: Alaska Airlines maintained its top spot by scoring in the top three in several key criteria including airfare, on-time arrivals, customer satisfaction, baggage handling, and its frequent flyer program.
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"A brief third-party technology issue that prevented some Delta Connection flights from being dispatched on time this morning has been resolved," Delta said.
Other airlines also reported a series of delays as a result of the problem.
Southwest Airlines was the first carrier to report that the problem had been resolved and it would get travelers moving soon, before later adding customers should expect flight delays.
One Southwest passenger reported waiting on the tarmac in Dallas for 90 minutes after his 6 a.m. flight to New Orleans was delayed. The airline said after the systems resumed that the flight would arrive at 8.05 a.m.
Other passengers reported long wait times at airports and missed connections.
(Reporting by Sanjana Shivdas in Bengaluru and David Shepherdson in Washington; editing by Patrick Graham)