The Federal Aviation Administration (FAA) temporarily halted flights arriving at New York City airports and Philadelphia on Saturday.
The shutdown came after a trainee at the New York Air Route Traffic Control Center tested positive for the novel coronavirus.
Reuters reports the FAA lifted the order in the afternoon but some flights were still being delayed while flight management returned to normal.
The positive test forced the FAA to close some air space sectors and reroute flights.
Flight tracking website Flightaware said 600 flights had been canceled on Saturday at John F.
Kennedy and Newark airports.
The FAA has had a series of issues this week due to cases of the coronavirus that causes COVID-19.
Earlier this week, it forced the cancellation of more than 2,000 flights and the closing of towers at Chicago Midway and Las Vegas.