Boeing was generating optimism. Then on Thursday a 787 crashed, raising the specter of fresh problems for Boeing and altering the message it planned to send.

Fatal crash raises new concerns for both firms as they try to revamp after years of problems that marred reputations.

The deadly crash of an Air India flight carrying more than 240 people on Thursday arrives after years of efforts to turn around the country’s flag carrier — which had been plagued by tragedy and financial losses under prior state ownership.