Mitsubishi Heavy Industries Ltd. has delayed the debut of its regional jet for the sixth time, raising questions about whether years of investment in the SpaceJet were worth the effort.

Deliveries of the aircraft, which had been slated for the middle of this year, will now be pushed back until after the fiscal year ending March 2022, the manufacturer said Thursday, adding that it was taking a ¥496.4 billion ($4.5 billion) charge on the program.

The SpaceJet represents Mitsubishi's effort to take on Embraer SA and capitalize on growing demand for short-haul flights. The plane, the first Japan-built airliner since the 1960s, accommodates about 90 passengers.