The plane was in Belarusian airspace so it isn't really comparable to "a Nato country's plane over Nato airspace" but if what happened in and around Cuba didn't

The plane was in Belarusian airspace so it isn't really comparable to "a Nato country's plane over Nato airspace" but if what happened in and around Cuba didn't start WW3 then a single plane diverted (and maybe a dissident or two kidnapped) would hardly register in the big picture. In fact several planes did get diverted and some even shot down during the Cold War and it rarely caused any further incidents.