BROOKSVILLE — Rescuers still haven’t found an airplane that disappeared Sunday morning near Cedar Key or the three people who were inside, the U.S. Coast Guard said. Crews were combing a search area that stretched more 150 square nautical miles south of the island. On Monday, they found a seat cushion, a headset and a flight manual they believe came from the cockpit of the Piper Cherokee. They found no plane parts. “We continue to remain hopeful,” Coast Guard spokesman Michael De Nyse said. Jasper Jerrels, 65, his 17-year-old son and 60-year-old Hue Singletary took off from Brooksville-Tampa Bay Regional Airport on Sunday morning bound for Cedar Key, where they were going to have lunch, Coast Guard officials said. The plane last appeared on radar about 7 miles south of the island at 11:06 a.m. Sunday, according to the Air Force Rescue Coordination Center. Hours later someone contacted the Gainesville flight service station, a Federal Aviation Administration office that provides information and flight planning services to pilots, to alert officials about their absence. At 5:21 p.m., officials in Gainesville contacted the Coast Guard’s St. Petersburg sector, which began searching. No flight plan was filed for the flight and one was not required. If one had been filed, officials could have known sooner the plane didn’t make it to Cedar Key. Coast Guard officials also confirmed rescuers did not receive a beacon signal from an emergency locator transmitter, a device commonly found aboard small, general aviation aircraft that sends a distress…more detail