A cross country commercial air flight made an emergency landing in Denver Wednesday night over possible security concerns. United Airlines Flight 1243, from Newark to San Diego, landed at about 9:30 p.m. at Denver International Airport, said Heath Montgomery, a DIA spokesman. The diverted flight was greeted by Denver police and FBI agents, Montgomery said. Buses were used to get passengers off of the plane and to a DIA concourse. Montgomery said the unscheduled landing was because of “possible security concerns.” The flight took off from Newark at 6:50 p.m.