Trouble developed Wednesday aboard millionaire adventurer Richard Branson's hot-air balloon somewhere over the Pacific Ocean, and preparations were being made to ditch the craft, organizers said.

After months of waiting for the proper atmospheric conditions, Branson and pilot Per Lindstrand lifted off from Miyakonojo, in southwestern Japan, on what they had termed the last possible day for launch, project organizers said.The pair had gone more than 2,000 miles and had hoped to land near Los Angeles, more than 6,000 miles from Japan, in 42 hours, Will Whitehorn, a project spokesman, said.

But fuel difficulties developed aboard the craft and "it now seems likely that the flight will end within 10 to 24 hours," a spokeswoman in Los Angeles said.