A grounded Boeing 787 Dreamliner jet operated by United Airlines is parked at Los Angeles International Airport (LAX) on January 17, 2013 in Los Angeles. (David McNew/Getty Images)
TOKYO -- Boeing executives say commercial flights of its grounded 787 jets will resume "within weeks, not months" with a third of safety tests already completed.
They said Friday they had not pinpointed the causes of the two battery problems that resulted in the global grounding of the technologically advanced Dreamliner planes.
But Boeing chief project engineer Michael Sinnett said a new design has many layers of safeguards to prevent battery fires and overheating.
The new design has measures to contain the problem from spreading and to keep the aircraft safe, even if batteries malfunction again.
The executives made the comments in Japan, where All Nippon Airways was the launch customer for the 787.