The Piper PA 46 aircraft was flying at about 2,000ft when the emergency call came in, a Federal Aviation Administration (FAA) spokeswoman said.

According to a recording on the website LiveATC.Net, the unidentified pilot calmly radioed "mayday, mayday, mayday", and told an air traffic controller a door was open.

"I have a door ajar and a passenger that fell down. I'm six miles (9km) from Tamiami," the pilot said.

"You said you've got a passenger that fell out of your plane?" the air traffic controller responded.

"That's correct, sir," the pilot continued. "He opened the back door and he just fell out the plane."

Coast Guard and Miami-Dade Fire Rescue air and water units launched a search southeast of Tamiami Executive Airport, where the plane landed safely.

It was not immediately clear where the flight originated or how many people were on board.

Officials have not confirmed whether the pilot's emergency call was legitimate, and FAA investigations are ongoing.