Flights Grounded Across U.S. After F.A.A. Failure

A Federal Aviation Administration system failure caused some flights across the United States to be grounded, the agency said early Wednesday.

The full extent of the delays was not immediately known, and some flights had taken off, but the delays were spread across several airlines. More than 1,100 flights within, into and out of the United States had been delayed on Wednesday, and more than 90 were canceled, according to FlightAware, a flight tracking company.

United Airlines said in a statement that it had temporarily delayed all domestic flights and that it would issue an updated when it learned more from the F.A.A.

On social media, would-be passengers across the United States said their flights had been delayed, some reporting that their pilots or airline representatives had cited the F.A.A. technical problem.

Several airports, including in Philadelphia, Tampa, Fla., and Austin, Texas, advised passengers to check with their airlines for the latest information.

This is a developing story.