Iran mistook PS752 for a cruise missile [0]. It's not an impossible mistake; a cruise missile is (often) a subsonic, jet-powered object.

[0] https://en.wikipedia.org/wiki/Ukraine_International_Airlines...

Point of order: A cruise missile isn't a high-speed missile. It's (almost?) always a big, slow, lumbering bastard, as far as missiles go.

There are cruise missiles powered by ramjets that go significantly supersonic, but for the most part ballistic missiles are easier to use, longer range, and harder to intercept. The prospect of anti-air systems effective enough to pose ballistic missiles trouble in a "near-peer" non-nuclear conflict is recent. Both maneuvering-capable ramjet/scramjet cruise missiles and (the significantly easier) maneuverable hypersonic re-entry vehicles that launch ballistically, are the subject of recently fielded early models, active development & active testing because of that prospect.

Hence the term "cruise", which in every other context means not traveling especially fast.

Airliners aren't slow by cruise missiles standards: supersonic cruise missiles are few and far between, and most cruise missiles in fact fly roughly at the speed of an airliner (between 800 and 1000km/h).

You're the second person to talk about cruise missiles in this subthread.

The comment I replied to (and quoted in my reply) talked specifically about "high-speed missiles". Nearly all cruise missiles are most emphatically NOT that sort of missile.