Cessna plane crashes onto world's busiest freeway

A small plane crash-landed on the world's busiest freeway in California on Friday (local time), exploding into flames on impact.

The Cessna 310's pilot reported engine trouble and tried to return to the nearest airport, but fell just metres short of the runway.

"We got a mayday! We got a mayday!" the male pilot shouted to FAA controllers in audio released by the control tower.

"Your landing gear appears to be up," a male voice replied.

"I know," the pilot said. "We're still trying to get a little altitude... I just lost my right engine."

The plane then crashed onto the 405 Freeway near John Wayne Airport and burst into flames.

Two people escaped and were taken to hospital with serious injuries.

The exact cause of the crash is unknown.