Ground activity was halted for several hours Newark Liberty International Airport after pilots reported seeing drones above the runway at nearby Teterboro Airport. One pilot approaching Teterboro reported that he almost collided with one of the unmanned aircraft, in an area that fell within Newark’s airspace. “Missed the drone by about 30 feet off our right wing,” he said, according to audio from the airport’s air-traffic control obtained from the website liveatc.net by ABC News. Federal Aviation Administration spokesman Greg Martin told ABC News that two drones were spotted flying at about 3,500 feet above Teterboro—a critical altitude for flights both taking off and landing at the private-plane facility. Officials did not find the drones or their pilots, but an investigation is underway.