American Airlines flights back in the air after a technical issue grounded all its planes across the US

• American Airlines briefly grounded all its US flights over a technical issue on Tuesday morning.
• The airline told BI that a "vendor technology issue" had affected its flights.
• Certain cancellations and delays trigger compensation under new federal rules.

American Airlines grounded all its flights across the US for about an hour on Tuesday, saying it was experiencing technical issues.

Later Tuesday morning, American flights were back in the air. It was unclear whether the delays would reverberate through its network and cause additional issues on a big travel day ahead of Christmas.

Under new Department of Transportation guidelines, some passengers could be entitled to compensation if their flights are delayed or canceled.

The Federal Aviation Administration said in an advisory statement early on Tuesday that the airline's flights across the US were grounded. An update about an hour later said the nationwide ground stop was canceled.

American Airlines told Business Insider in a statement that a "vendor technology issue briefly affected flights." That issue has been resolved, and flights have resumed.

"We sincerely apologize to our customers for the inconvenience this morning," American said. "It's all hands on deck as our team is working diligently to get customers where they need to go as quickly as possible."

The airline said that the technology issue affected the systems needed to release flights and that the ground stop lasted about an hour.

Bloomberg described online posts as saying the issue prevented the airline from calculating weight and balance requirements for its flights.

About 1,000 flight delays on Christmas Eve

The flight-tracking website FlightAware showed that about 1,000 American flights, including its regional subsidiaries, were delayed on Tuesday morning across its hubs in Charlotte, North Carolina; Miami; Philadelphia; Washington, DC; Phoenix; and Dallas/Fort Worth.

But none were canceled, and planes were getting back in the air by mid-morning Eastern Time. Most flights were running one to two hours behind schedule, with some reaching three hours.

Charlotte and Dallas/Fort Worth were the most affected airports, with more than 300 flight delays each. A weather advisory in effect in the Dallas area was further disrupting flights.

It's unclear how these delays would affect afternoon flights as the airline tries to catch up.

Federal rules about customer compensation

Users on X said they were made to get off their planes on Tuesday morning.

New Department of Transportation rules say customers are entitled to automatic refunds for flights that are canceled or "significantly changed," including domestic flights that arrive at least three hours later than scheduled. To receive a refund, a customer must not accept a changed booking.

Most airlines, including American, offer meal vouchers to travelers who wait three or more hours because of a delayed or canceled flight that was within the airline's control. American's technical issues would fall under that category.

Many provide hotels for an overnight delay or cancellation, as well as transportation to and from the airport. It's unclear whether American's Tuesday disruptions will spill over into Wednesday.

The disruption comes on Christmas Eve, one of the biggest travel days of the year.

The Transportation Security Administration said it expected to screen almost 40 million people through airports over the holidays, an increase of more than 6% from last year.