IT issues at Frontier Airlines triggered a brief ground stop at all of the U.S. budget carrier's destinations on Thursday evening, according to an advisory from the U.S. Federal Aviation Administration.

Frontier Airlines issued a complete ground stop for all nationwide flights amid ongoing IT issues, according to an advisory by the FAA. It was lifted after a half an hour

Frontier Airlines has grounded all flights across the US due to IT issues, the FAA advisory says. Frontier Airlines serves over 100 destinations across the United States, Mexico, the Caribbean, and Latin America.

Frontier said in a release that it has met with Spirit’s board and executives since it made its proposal this month.

Spirit, which filed for bankruptcy protection last year, says it has rejected the new Frontier overture but would be open to a higher offer.

Discount carrier says a merger would be a better path out of bankruptcy for Spirit, which has rebuffed the latest proposal.