Intended.<p>Planes are too fast and too maneuverable. Especially military planes — SAMs weren’t actually designed to down civilians. That’s why missiles have proximity-based detonators, so called “proximity fuze”, to explode at the right moment.<p>BTW, here’s 8 minutes video about the history of that technology: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Kq_Uy5hGazc" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Kq_Uy5hGazc</a>