This was one of the factors that guided Putin's thinking when he took Crimea.
There's nothing preventing Ukraine's allies from setting up air defenses and fighter patrols to shoot down drones and missiles. A number of countries did just that when Iran launched a missile attack on Israel last year.
And Russia would go back to planes if other countries were shooting down their missiles, because they know that other countries would hesitate to declare war by shooting down one of their planes. Other countries taking over this responsibility neutralizes the air defense against planes.
Can't argue with NATO forces effectiveness in that operation though.
The campaign was valuable to everyone involved. The US got to assert itself as a global moral authority, also finally getting to build Camp Bondsteel[0] after decades of trying to build a base in the region (the largest US base on foreign soil since Vietnam, and it was built and managed by KBR meaning Dick Cheney and his shareholders also profited considerably; they've since lost interest so nowadays it's just a mini Gitmo). For the allies that backed them and helped justify the war, they received carte blanche permission to do what they like and settle their own scores. Their Dutch friends, for example, got to brazenly violate international law from the start by dumping their out-of-date depleted uranium cluster bombs on my densely populated home town[1], choosing to target the main building of our university, the main building of our city hospital, and the biggest civilian central steam heating plant that kept half the city warm.
The campaign did have some negative effects though. In the east it was interpreted as a deliberate provocation toward Russia at a time of particular weakness (their president getting hammered and falling out of planes etc), and Putin used this extensively as an example of Russian embarrassment at the hands of the US, helping him rise to power as PM in August '99, acting President in December '99, and President in March '00.
I'm not particularly emotional about any of this btw - I just thought you'd appreciate the geopolitical perspective and the ripple effect that war had on Russian politics & subsequent opinion towards the West.
Ukraine needs the same kind of support, but instead, they got misguided "de-escalation" that only boxed Ukraine in and gave the initiative to Russia. By knowing that the US would force Ukraine to throttle back every time the Russians made a large misstep, Russia was encouraged to keep escalating without the fear of triggering an overwhelming response.