An air-traffic facility that oversees flights over most of northern Texas was temporarily evacuated Wednesday because of smoke, prompting flight disruptions to both of Dallas’s commercial airports.

Controllers were back on the job at 1:46 p.m. local time, more than hour after they were forced to leave the facility, the Federal Aviation Administration said in a statement.

Southwest Airlines Co. was forced to cancel 70 flights and divert an unspecified additional number “to help manage current traffic and support operational recovery once the ground stop is lifted,” said Brandy King, a spokeswoman. Southwest’s Dallas-area traffic flies out of Love Field.

The disruption caused American Airlines to divert 28 flights to other cities, a spokesman for the carrier said. American’s largest hub is at Dallas/Forth Worth International.

Air-traffic personnel temporarily moved to two control towers at Dallas/Fort Worth to help provide at least limited service, the FAA said. Those facilities remained open and have similar radar tracking as the evacuated center.

The FAA center, known as DFW Terminal Radar Approach Control and also located at the Dallas/Fort Worth airport, was undergoing construction when smoke was reported, the FAA said. The evacuation was reported at 12:30 p.m. local time.

After earlier reporting delays at DFW of as much as an hour and 15 minutes and increasing, an FAA website reported delays were minimal at 2:07 p.m.