Well, plenty of potential things. In strictly defence terms, they buy weaponry from US and Germany. Hungarian air force operates Swedish Gripen fighters and thus most likely relies on Sweden at least for spare parts (which military jets need lots of) so here's another pressure point. They are big beneficiaries of EU funding (not a NATO thing but this is all intertwined) and already at odds with EU rules, which could push them towards not getting the funding - there are plenty of reasons to implement that already, just lacking political will right now. They can find themselves sidelined for new EU spending, political nominations, and so on.
The question would of course be if EU/NATO want to do that. It's part of the usual political horse-trading game.
For sure, in the extreme scenario if US/EU/main partners really wanted Finland and Sweden to join and Hungary vetoed, it could be made to pay an unaffordable price.
Didn’t the US/EU take the high moral of self determination for every country, when supporting Ukraine’s actions? So, if Hungary “self determines” to veto access to NATO, which is its right according to NATO’s rules, why punish it and suffer consequences? It would be the same as Russia invading Ukraine to punish it for “self determining” its choice to join NATO or the EU. I don’t care about rhetoric and window dressing. I want to argue the raw facts. I feel most people here are hypocrites. Let’s agree that the US and EU are equal bandits as Russia. Let’s all drop the hypocrisy.
I don't think there is much demand for JAS Gripen in Nato countries at this day. 4th gen fighters do not have much lifetime left in them, and F35 is increasingly taking the role of the current-gen fighter for advanced nations.
But Sweden is already member of the Cuture Combat Air System (FCAS) initiative to create a 6th gen air war system of systems, alongside nato members. And this kind of colaboration will be even more natural when/if they join Nato.
Dunno. If it was something else, I'd be tempted to agree. But Sweden deciding to join NATO, everyone but Hungary agreeing, Sweden stopping parts? Not sure. It's a, well, minor act of military... aggression? Extreme unhelpfulness for sure.
Also the real question would be, would Hungary see it as a credible threat. Were they to go ahead with that, they'd find themselves with no airforce and unhappy allies. That sounds like a raise they couldn't afford to raise.
The question would of course be if EU/NATO want to do that. It's part of the usual political horse-trading game.
For sure, in the extreme scenario if US/EU/main partners really wanted Finland and Sweden to join and Hungary vetoed, it could be made to pay an unaffordable price.