Toyota Motor Corp. said Wednesday it may invest in Mitsubishi Heavy Industries Ltd.'s project to build a regional jetliner that would be the first commercial aircraft produced domestically in around four decades.

Toyota, Japan's No. 1 automaker, is "considering a request received from Mitsubishi Heavy for investment (in the project). But no decision has been made," Toyota spokesman Toshiaki Hori said, declining comment on when a final decision may be made.

Toyota's possible participation is likely to boost Mitsubishi Heavy's project to develop Japan's first domestic passenger aircraft since production of the YS-11 twin turboprop ended in 1973.