Departures across the U.S. were halted for two hours Wednesday morning after the agency's system for alerting pilots and airports of real-time hazards went dark, frustrating thousands of travelers.

The transportation secretary is one of the many travelers who had their flights cancelled in recent days. His happened the day after he met with airline CEOs about their operational struggles.

The transportation secretary is one of the many travelers who had their flights cancelled in recent days. His happened the day after he met with airline CEOs about their operational struggles.