"We will be eager to hear his thoughts on state sovereignty and independence once he has broken free from his dependence on Russian energy, as U.S. President Donald Trump and European partners insisted multiple times," Foreign Minister Andrii Sybiha said.
Just because Hungary is a NATO member doesn’t make all their troops and equipment NATO. E.g. if you’re a soldier crossing into another member’s territory, you need a NATO travel order to prove that your presence is warranted and actually covered under the treatment. And even then, Ukraine isn’t a NATO member nor have they given a permission for NATO members to violate their airspace.
Violating another country’s airspace with military aircraft is pretty high on the don’t do list; Ukraine could in return close its airspace to Hungarian aircraft