A helicopter caught on fire early Friday while on the ground at an airport in Hanson, Massachusetts.The incident happened at the Cranland Airport on Monponsett Road, fire officials said.The 81-year-old man who owns the helicopter, which was built from a kit, said he took it out to fly, started it and it caught on fire.The man said he smelled gas upon starting the helicopter’s engine. He exited the aircraft just as the fire ignited.No one was on the aircraft at the time of the fire, officials said. There were no injuries reported, and the cause of the fire remains under investigation by the Hanson Fire Department.