Alenia Aermacchi has achieved military-type certification for its M-346 trainer from the Italian defence ministry,
The company's chief executive, Guiseppe Giordo, said the move was a "major milestone" for the programme that demonstrated "the maturity" of the jet.
It is currently being pitched in four trainer or fighter competitions in Poland, the USA, Nigeria and Israel.
Poland is the most important of these as it asks for both trainer and light combat variants of the aircraft, said Giordo.
"We believe we have a good opportunity to win the Polish competition and go on to develop that configuration for other customers," he said.
The Polish request for proposals is expected shortly, with a decision possible by the end of the year, said Giordo.