The production of the Boeing 787 Dreamliner aircraft continues at two of the company’s factories despite the airplane being grounded by the Federal Aviation Administration, reports The New York Times.

Flights for the 50 active Dreamliners have been on hold for more than four weeks, as the FAA-imposed grounding is now in its fifth week. There is speculation that the sanction could remain in effect indefinitely.

The F.A.A.’s emergency airworthiness directive, issued on Jan. 16, did not specify how long the 787 would be prohibited from flying. But a growing consensus suggests it will be many months before the plane will fly again. Decisions will depend on what safety investigators learn about the cause of smoke and fire incidents in the battery compartments of two Japanese Dreamliners on Jan. 7 and Jan. 16.