A computer problem forced United Airlines to ground all domestic flights for about an hour on Sunday evening.
The problem created a series of flight delays which annoyed customers throughout the United States.
The “ground halt”, which the unit of United Continental Holdings Inc disclosed in a tweet at 8:06 pm ET.
The halt was lifted about an hour later, follows a series of problems at United and other airlines last year.
International flights were not affected, the Federal Aviation Administration said. The number of flights that were affected was not known.
“The ground stop has been lifted. We’re working to get flights on their way,” United said in a tweet.
United said it would waive change fees for passengers with a ‘travel waiver’.
However, passengers took their frustration to social media and the Chicago-based airline started responding to their tweets.
“This has been the worst customer service experience and worst flying service ever experienced in 30+ years,” one passenger tweeted.
“My minor son, the one stuck in Tampa with a tumor in his skull?
“You just told him he can’t stay in a hotel. What’s your plan?” another passenger tweeted.
United responded to this woman’s tweet to asking for her son’s travel details.
“We are working as quickly as possible to resolve this issue and get out customers to their final destinations.”
Recall that in October last year, thousands of United passengers were delayed worldwide after a computer glitch temporarily halted departures.
In June, a software needed to dispatch United’s flight plan briefly lost functionality.
The same problem happened in July, disrupting flights.
Last week, Air Canada and Toronto-based Porter Airlines also experienced brief glitches that prompted some flight cancellations.