Yesterday, Ukraine launched an An-2 biplane loaded with explosives against the Russian refinery in Salavat, located 1,400 km from the Ukrainian border. The fact that a biplane like the An-2 managed to travel 1,400 km through Russian airspace reveals a lot about the precarious state of Russia’s air defenses in the country’s interior. This also helps explain why Putin reacted so furiously to Ukrainian attacks with long-range weapons.