A trainer jet manufactured by Leonardo crashed near the town of Como in northern Italy on Wednesday and one of the two pilots has died, the defence group said.
Witnesses in the area reported seeing a fireball crashing on the mountain wall.
Two helicopters from Como and Milan immediately took off to search the aircraft.
The cause of the accident is under investigation, the state-controlled group said in a statement, adding that emergency vehicles were operating in the area of the disaster and that the company had activated an internal investigation.
“Leonardo expresses its most heartfelt condolences,” the group said, adding that it could provide further updates in the next few hours.