Following a brief outage that grounded all American airlines flights during one of the busiest travel periods of the year, American Airlines says it has resumed service Tuesday morning, albeit with substantial delays.

American Airlines said on Tuesday its flights had resumed after a technical glitch forced the carrier to issue an hour-long ground stop, disrupting travel for thousands on Christmas Eve, one of the busiest periods of the year.

American Airlines requested a nationwide ground stop, which was later canceled, on the morning of Christmas Eve due to technical problems.