A telecom outage on Friday caused delays at Dallas airports, affecting over 1,800 flights and canceling hundreds, mostly for American Airlines and Southwest.

The FAA said the issue was with local telephone equipment, not FAA systems, and worked to resolve it. Departures to Dallas Fort Worth were halted until 11 p.m., and Dallas Love Field until 8:45 p.m.

American Airlines canceled 200+ flights and delayed 500+, while Southwest delayed 1,100+, hitting about a quarter of their schedules.

FAA communications problems have been ongoing, with aging systems and staffing shortages prompting a $12.5 billion congressional upgrade after several recent mishaps.