US adventurer Steve Fossett is on the brink of achieving the first solo, non-stop flight around the globe.
The attempt is progressing well despite some hitches
Despite a fuel shortage, the pilot had crossed the coast of California just before 1400 GMT and is expected to land in Kansas at about 1920 GMT.
The millionaire had considered aborting the trip and landing in Hawaii, but he decided to press on because of favourable tail winds.
Mr Fossett said he was "really starting to perk up" as he neared the end.
Flight sponsor Sir Richard Branson said the team was "reasonably confident that by midday... he will make it".
"He's a great glider and so if he runs out of fuel before he gets here he will somehow, we hope, make it all the way," the Virgin Atlantic chief told ABC television.
'Let's go for it'
Mr Fossett left Kansas on Tuesday.
On Wednesday, there had been speculation the 60-year-old might have to land the GlobalFlyer craft because of an unexplained loss of fuel.
Project manager Paul Moore said wind conditions and the fuel situation had improved between Japan and Hawaii, prompting Mr Fossett to tell mission control: "Let's go for it."
When asked how he felt after his second full day of flying, Mr Fossett told reporters via satellite phone: "It feels like three days.
"I've gotten minimal naps while keeping my eyes on the instruments," he added.
Sir Richard said earlier he was confident that adrenaline would kick in as the pilot neared his goal.
Checks revealed on Wednesday that the vehicle was missing 1,200kg (2,600lbs) of fuel.
Mission controllers have been at a loss to explain the discrepancy - whether the plane was incorrectly filled on the runway, or if it burnt off too much fuel in the early stages of the flight.
VIRGIN ATLANTIC GLOBAL FLYER - LONG-DISTANCE JET PLANE
(1) Fuel tanks - Gross weight is 10 tonnes; empty weight is 1.5t
(2) Engine - Williams FJ44-3 ATW (10,200 Newtons of thrust)
(3) Cockpit - Pressurised and large enough for pilot to lie down
Length - 11.7m; Height - 3.6m; Wingspan - 35m
Speed - in excess of 460km/h; 290mph; 250 knots