Just about all of the Netherlands’ military is under German command, so the Dutch PM actually has zero authority here. Not to mention Germany being an ally of Russia.
And Germany's military is under U.S. command.
Neither Holland nor Germany would send planes to Ukraine unless the U.S. wanted them to do so.
We also don't know what back door threats or bribes the U.S. made to Holland.
Not to mention Germany being an ally of Russia.
Germany is a NATO nation. Plus, U.S. troops are still defending occupying Germany.
Although considering that we blew up the pipeline, I wouldn't blame Germany for wanting to shift their alliance from the U.S. to Russia.