Watch HDToday. Enrico Mattei helped change Italy’s future, first as freedom-fighter against the Nazis, then as an investor in methane gas through a public company, A.G.I.P., and ultimately as the head of ENI, a state body formed for the development of oil resources. On October 27, 1962, he died when his private airplane crashed during a flight to Milan. Officially, it is declared an accident, but many journalists explore other plausible reasons for Mattei's untimely death.