There's a Frenchman claiming that the US Navy shot down the Malaysian airlines Boeing 777 that went missing this year.
It's just a theory, but the argument for such a policy is much easier than the torture policy we've been discussing below. On the one hand, it's always wrong to intentionally kill the innocent. On the other hand, the people who put the innocent in a position of needing to be killed to avoid a great harm are not members of the US Navy, but members of the enemy organization that hijacked the plane for presumably terrorist purposes.
So unlike the case of torture-for-information, here we have a case that is really justified. If this was done, the harm lies on the wicked who hijacked the plane for evil reasons.