Massive computer outages caused significant confusion and travel delays at major US airports on Monday.

Multiple airlines experienced system-wide outages that affected their operations across the United States. Travelers across the country were facing serious delays Monday morning amid the outages. Delta, Southwest, and American Airlines sent out tweets acknowledging the issues early in the day. Delta and Southwestern both reported the issues as “system-wide” outages, but American Airlines didn’t initially specify the scope of the problem.

The FAA released a statement explaining that the airlines were facing challenges with “a flight planning weight and balance program called Aerodata. Mainline operations and regional operations are impacted to varying degrees.” The issue was solved during the early hours of Monday morning.

The system-wide outages had an ongoing effect on travel times, but everything was pretty much cleared up by the end of the day. Service interruptions of this nature are rare, but they can still happen. If you have a flight scheduled, it’s always better to check flight updates in order to avoid unnecessarily wasting time.