In the first scene of Ant Man, we see Howard Stark alive and healthy in 1989. So when did he die? And how? Is the answer different in different timelines?
Note: This is not a spoiler because you see it in the first few minutes of the movie.
Howard and Maria Stark were killed in an automobile “accident” secretly arranged by HYDRA on Long Island in 1991, to remove him as an obstacle in their plans.
Here is the Youtube clip form Captain America 2 to prove that and following is the screenshot:
After Captain America: Civil War we came to know that:
Winter Soldier killed Howard Stark and his wife to steal the super soldier serum and made it look like a car accident.
In the comics, per Wikipedia
In the comics, Howard and his wife Maria died in a car crash, as the result of faulty brakes arranged by either business competitors Republic Oil & Gas (later Roxxon Energy Corporation) or by the V-Battalion.
In Civil War we see that Bucky was under HYDRA's control, and he unwillingly crashed his car into the car with the Stark family. Then, Bucky got out and hit poor Howard on the side of his head multiple times, and strangled Mrs. Stark.
According to the comics, the canonical status of Howard Stark is that he is currently alive( or at the very least his fate is unknown). As for Maria, well that is a complete mystery.
In issue #1 of Jonathan Hickman’s run on “S.H.I.E.L.D.” While dicussing their families and duties Stark explains to Nathaniel Richards that due to the delicate natures of their mission the Brotherhood of the Shield arranged for the “deaths” of both agents. Stark continues to explain that his death was staged as an “automobile accident”. For whatever reason Maria’s involvement and ultimate fate is never mentioned.