Mitsubishi Aircraft Corp., building Japan's first passenger jet, said it will announce a new schedule for the maiden flight because the company is facing "challenges" in its development.

The new flight schedule for the Mitsubishi Regional Jet will be decided in "a few months," Yugo Fukuhara, director of marketing, said Wednesday at the Singapore Airshow. He declined to say whether the MRJ's first flight will take place this year, as planned.

The unit of Mitsubishi Heavy Industries Ltd. may soon announce new customers for the jet and is in talks with several parties, Fukuhara said. The company began building the jet at a plant in Nagoya last year and expects to sell about 1,000 over the next two decades, challenging Bombardier Inc. and Embraer SA.

"There is sort of a very long way to the development of the airplane and we are always facing some challenges," Hitoshi Hank Iwasa, vice president of sales and marketing, said at the air show. "We are very confident to overcome these challenges."

The company has won orders for about 130 MRJs from airlines, including All Nippon Airways Co., Trans States Airlines Inc. and ANI Group Holdings Ltd.

Mitsubishi said earlier the MRJ's first flight would take place in the second quarter of this year and the first delivery is slated for the first quarter of 2014.