Mitsubishi Heavy Industries Ltd. is planning to slash the number of employees working on its struggling regional jet business amid bleak demand for aircraft due to the coronavirus pandemic, sources close to the matter have said.

The plan, revealed Friday, comes as its aircraft subsidiary, Mitsubishi Aircraft Corp., has repeatedly delayed the first delivery of a small passenger jet, called the Mitsubishi SpaceJet and previously known as the Mitsubishi Regional Jet, due to parts problems.

The Mitsubishi Heavy unit plans to downsize mass production of the 90-seat class passenger jet it aims to begin delivering in fiscal 2021 or later, the sources said.