This isn’t much different than the question of “aborting” an
ectopic prenancy. A fetus which implants in the fallopian tube has absolutely no chance of survival - it is medically impossible (unless some major medical breakthrough has been recently made). But, unless removed, this condition will kill the mother. I’ve never heard a moral theologian object to an abortion under these circumstances - though I’ll probably hear from some now
Kill one person (with NO chance of survival) to save another? Sure. Passengers aboard a plane piloted by a murdering maniac have the same chances of survival as an ectopic pregnancy.
But what if a terrorist hit squad hails a taxi and heads to New York intent on mass meyhem… an F14 flying overhead has a small window of opportunity to bomb the cab (but no other options) before it gets lost in city traffic. But bombing the cab would kill the innocent and unwitting driver (who probably would not number among the terrorists intended victims). That gets harder to justify.