Boeing sent a 787 up on a test flight Saturday, the first since the new airliner was grounded three weeks ago because of a battery fire.

The company said the aircraft was flying in and out of Boeing Field in Seattle. The plan was to spend two and a half hours in the air, flying back and forth over the inland Columbia Plateau.

The Federal Aviation Administration granted permission for test flights on Thursday.

The 787 is the first commercial airliner to rely heavily on lithium-ion batteries, the same kind used in cellphones. Each plane has two of the 63-pound blue power bricks, one near the front to provide power to the cockpit if the engines stop, and one near the back to start up the auxiliary power unit, which is essentially a backup generator.

On Jan. 7, a battery on a plane that had recently landed in Boston short-circuited and caught fire. Nine days later, a battery on an All Nippon Airways plane started smoking, forcing an emergency landing in Japan.

Boeing Co. has billions of dollars tied up in research on the 787, and billions more dollars in 787s parked in Everett, Wash., and other sites that are waiting to be delivered.