Toray, which is a major supplier of light weight carbon fibre components to aircraft makers, had planned to supply stabilizers for the SpaceJet's tail. Those part will now be built in-house by Mitsubishi Aircraft, a unit of Mitsubishi Heavy Industries, the Nikkei said.
Officials at Toray and Mitsubishi Aircraft were not immediately able to comment.
Originally meant to go into operation in 2013 with Japanese airline ANA Holdings, the Mitsubishi plane has been delayed five times. Mitsubishi Aircraft is considering a fresh delay as it struggles to gain certification for the regional jet.
(Reporting by Tim Kelly; editing by Simon Cameron-Moore)