Boeing and the FAA ended up grounding all of its 787 Dreamliners last month due to multiple reports of battery failures. Both US-based and international airlines ended up grounding the entire 787 fleet in order to get to the bottom of the issue, and while investigators are making progress into the failed battery problems, they say that there's no rush and no pressure to get it done as soon as possible.
Reuters reports that the investigations into the failed batteries are going well so far. Kelly Nantel, spokeswoman for the U.S. National Transportation Safety Board, says that "investigators are moving swiftly and we are making progress." Authorities from the US, France, and Japan are all investigating into the matter.
However, according to Bloomberg, US Secretary of Transportation Ray LaHood (who recently just stepped down from the position), says that investigators are "not feeling any pressure," and mentioned that the team is "going to get this right," meaning that they're not taking any shortcuts whatsoever in order to get the planes back in the air.
However, this means that there's no specific timeframe when Boeing and the FAA will have the 787 Dreamliners flying again. Tom Haueter, aviation investigations chief at the NTSB, said that the investigation could take years to complete, based on the complexity of the evidence found during the battery failures. In the meantime, airlines are making due without their new 787s in service, and you can bet that Boeing is paying dearly for this incident.