Coast Guard vessels searched for pilot Stone Froberg for nearly 24 hours, but gave up at 12:30 p.m. When weather permitted, a Coast Guard helicopter also joined in the search.
Froberg, a San Diego resident, departed alone from Kearny Mesa's Montgomery Field in single-engine plane around 11:45 a.m. Friday. He was heading in a Cessna 172 to French Valley Airport, a small airport in the Temecula-Murrieta area, said Coast Guard Lt. Josh Nelson.
"He's a relatively new pilot," Nelson said.
Froberg was not required to file a flight plan and it is not clear why he was flying over water, Nelson said. The crash scene far off course, and about 75 miles away from the intended destination.
The small plane was registered to Golden Wings, an aircraft rental club and flight school in El Cajon. A phone call to the club was not immediately returned.
Nelson said they do not know what caused the crash, which was reported around 2 p.m. Friday by witnesses on a boat who saw the plane crash into the water.
Nelson said that, in a plane crash situation, the Coast Guard usually searches for 16 to 24 hours before presuming someone is dead and giving up the search.
With the water's temperature in the 50s overnight, anyone in the water for a long period of time is likely to suffer from hypothermia, Nelson said.
At least one U.S. Coast Guard vessel was plying the waters off Oceanside early today, looking for Froberg.
A helicopter search crew joined three Coast Guard vessels in the search shortly after sunrise this morning.
Nelson said some floating debris, including pieces of aluminum and some carpeting, was found about 30 miles off Oceanside more than three hours after the crash.
Some boaters who reported the plane hitting the water about 2 p.m. told the Coast Guard they were 20-30 minutes away from the impact site and found an oil slick when they got there.