NEW YORK United Airlines (UAL) is keeping the Boeing 787 Dreamliner on the ground at least until May 12.
Investigators are still trying to figure out what caused a battery fire and another battery problem last month.
"We are taking the 787 out of our schedule through June 5, except for Denver-Narita, which will tentatively launch on May 12," said a United spokesperson in a statement on Thursday.
The airline says flights from Denver to Tokyo's Narita airport that were supposed to start on March 31 will be postponed through May 11. If the 787 isn't ready to go by May 12, United says it will begin the Denver-to-Tokyo flights once the 787 is ready.
United says the plane could still fly earlier than that if a fix is found. At that point, it would be used as needed around United's system.
The world's fleet of 50 787s has been grounded since Jan. 16.