The experimental sun-powered plane, piloted by Swiss adventurer Bertrand Piccard, left Kalaeloa Airport at 6:15 am (1615 GMT) after strong winds delayed the flight around 75 minutes, images beamed live online showed.
"C'est beau! We are in the air," the 58-year-old pilot said as the aircraft left the runway.
The SI2 was grounded in July last year when its batteries suffered problems halfway through its 21,700-mile (35,000-kilometer) circumnavigation.
The crew took several months to repair the damage from high tropical temperatures during the flight's final Pacific stage, a 4,000-mile flight between Nagoya, Japan and Hawaii.
