Pilot Andre Borschberg, 62, left the ground in Nanjing, in eastern China, heading for the US island of Hawaii, at about 2:40 am (1840 GMT), after extended delays awaiting a suitable weather window over safety concerns.

Lit by white lights on its wings, the plane rolled down the runway before climbing into a misty sky with its four whirling propellers nearly silent.

Ground crew members cheered as it took off.

The 8,500 kilometre (5,270 mile) flight is expected to take an estimated 130 hours, organisers said.

"I cross my fingers and I hope to cross the Pacific," Borschberg told reporters just hours before the take-off.