At a tightly guarded factory in central Japan, Mitsubishi, maker of the Zero fighter jets of World War II, is launching its MRJ regional jet and aiming to fulfill Japan's long-cherished ambitions to regain status as a major aviation power.

The company said Friday that a recent decision to push back the jet's maiden flight from this spring to a few months later would not delay its commercial deliveries. Workers were conducting hydraulic and other tests on two of the test jets in a cavernous assembly facility; another jet had been sent out for painting.

Nobuo Kishi, a vice president of Mitsubishi Aircraft Corp., said the latest delay could speed things along because it is intended to allow for modifications that otherwise would be needed later.