LaHood made his first public comments about the Dreamliner since the FAA issued an airworthiness directive on Wednesday night grounding the 787. Since then 50 Dreamliners owned by 8 airlines around the world have been parked on tarmacs.
"Those planes won't fly until we're one thousand percent sure they are safe to fly," said LaHood.
(Read More: Are Lithium-ion Batteries Too Dangerous?)
Investigators in Japan
Friday in Japan investigators from the FAA, the National Transportation Safety Board and Boeing spent the day inspecting the All Nippon Airways Dreamliner that made an emergency landing after battery warning lights went off in the cockpit and the crew noticed an odd smell. Japan's Transport Ministry says a lithium-ion battery on that 787 failed, but it's still unclear exactly what caused the battery to fail. Investigators are looking at similarities between the Dreamliner battery in Japan and the battery that malfunctioned on a Japan Airlines 787 in Boston on January 7th.
(Read More: Boeing's Dreamliner Turns Nightmarish)