While I am also frustrated that many European states do not take their erga omnes obligations serious in regards to genocide, do I think shooting down a plane on the basis of a disputed warrant would not be a proportionate measure[^1].

Generally planes can be ordered to land, but if they ignore that call and there is no further threat (like many Russian planes), they will generally escort these planes until they are out of the airspace. States do this based on the prohibition of the use of force as defined in article 2 of the UN Charter.

[^1]: https://opil.ouplaw.com/display/10.1093/law:epil/9780199231690/law-9780199231690-e1138, '[T]here appears to be a measure of agreement at least insofar as a State can respond proportionally to the violation of its airspace by foreign aircraft (see Korean Air Lines Incident [1983]). However, there is an equal measure of disagreement as to the exact limits of this right. In any case, the principle of proportionality must be applied for every action taken. However, even in the light of these prerequisites, it is still highly disputed whether the downing of an aircraft constitutes a legitimate means in terms of ultima ratio'.

They are indeed tracked down by fighter jets and followed out of the airspace. My point was more that international law doesn't allow a state to just shoot stuff, even after a warning, when there is no immediate threat.

I share that sentiment.

It just doesn't mean international law means you can shoot whatever you want out of your airspace, nor if a state should want to set that precedent.

There are a lot of other things to consider, like which branch of international law is applicable here (not humanitarian law/law of armed conflict as there is no armed conflict between the concerned states and Israel).

Customary law is to be very careful shooting down planes that violates airspace (which I doubt is the case here, as I expect they were allowed to fly through their respective airspace).

Netanyahu is also not convicted yet. And not all states agree with the ICC's interpretation of head of state immunity.

There is some reality that needs to be taken into account, both that states have questionable views on Netanyahu, as well as that certain actions leads to unwanted consequences and/or precedents.

I'd rather focus on the fact that all states have an (erga omnes) obligation to prevent and concern themselves with the ongoing genocide, acts against humanity, and war crimes.

Finally, let's hope Netanyahu sets food in a state that will abide by the warrant and we see him in the Hague soon.