if one of these crashes, wouldn’t that be considered an act of war and trigger Article 5?
Article 5 is, ultimately, triggered by action within the EU. If Europeans want to treat this as another Boeing nosedive rather than a military action, they’ll wave it away.
As it stands, Vlad has been growing support within Southern European parliaments - Italy, Greece, France, Spain - and that might make invoking Article 5 more difficult than pointing at a downed airliner and proclaiming “Russia did this”.