Related question: was Hitler ever bothered by the brain drain of Jewish intellectuals leaving Germany? From what I know of his worldview, I always thought he'd discount non-"Aryan" thinkers for their "race" alone.
Edit: And what about other Nazi leaders? Did any of Hitler's senior subordinates ever grow concerned about losing intellectual talent?
So... there is a reason this question is unanswered and, in the literal sense, unanswerable. We don't know what Hitler thought about many things, and especially things which were inconsequential for him, which in the scheme of things this certainly was (Einstein had fled to the US years ago after all). Hitler did not keep a diary, and the collections of his private conversations is disjointed and nowhere near complete, being almost completely dependent on the post-war recollection of his intimates.
Proving a negative is hard, and for a question which is almost certainly "We don't know, and he probably didn't care anyways", few people actually are going to want to put in the necessary gruntwork, doubly so about a man who on a personal level was decidedly uninteresting (I would point to /u/commiespaceinvader's wonderful post here on this topic). 87 comments are in this thread, but most half of them are just replies to the Top Level Mod Warning, mostly either amused or horrified by the long, and hardly incomplete, catalog of questions about Hitler previously asked here. No one actually even made a serious attempt at answering, with the "best" being a few sentences speculating he didn't care, but without anything to support that, which was downvoted a few times before being removed. Beyond that is a mix of shitty puns, allusions to Hitler reaction videos, and people making the so original "[removed]" comment.
But for some reason the 57,400 who viewed this question want a damn answer, and for the few dozen of them who might still check back after 2 days (I would have done this earlier, but is hard when you're out of the country with no books), well, I've padded this out with META commentary, but the answer is what I said above, as well as what the lone removed 'answer' also stated. But this being AskHistorians, I can't very well just come out and say that unfounded, right?
So, much without further ado, here is a list of books which I searched for "Einstein" in (or "Hitler" in the case of Einstein books, and a few times "citizenship' when both terms occurred frequently). It is a mix of print books, in which case I used the index and eBooks/OCR'd PDFs in which case I simply plugged in the search term and checked every single instance where there was a mention. To be sure, this method is not conclusive, hence why I stated it is in the big scheme unanswerable. There is the chance of a source that I missed (As well as the chance of an OCR error in the PDF), and the much larger chance of an utterance left unrecorded, but the lack of mention in this wide array of books should at the very least give strong reason to doubt that Hitler gave a single shit that Einstein, who had lived in the US for the better part of a decade, now could use a passport instead of an Alien Registration Card...
So there you go. Again, not exhaustive, but fairly conclusive. And even without searching for a specific phrase, again, why would Hitler care? (cc /u/Taoiseach wrt their follow up question). The Nazis were quite happy to have one less Jew in Germany when Einstein decided to remain in the US after Hitler's rise to power. Hitler might not have remarked on incredibly minor and unimportant milestone for the 7 year resident that occured in 1940, but in the alleged interviews conducted by Richard Breiting in 1931, he is said to have remarked on Jewish intellectuals (although not Einstein specifically):
Everything they have created has been stolen from us. Everything that they know will be used against us. They should just go and foment their unrest among other peoples. We do not need them.
As I said, alleged, since there are questions about their veracity, the texts of the interviews only discovered decades after the war having been unpublished, but it is a general sentiment that can be said to be true. In the early '30s, after all, well before the implementation of the "Final Solution", earlier 'solutions to the Jewish problem' were hopes certainly included kicking them all out of Germany to be someone else's problem. although that said of course, once out of Germany and raising their voices elsewhere, the Nazis did sometimes find it necessary to comment further. Hitler didn't seem to have remarked specifically on Einstein's cutting away from Germany any more than his American later gaining of citizenship, but Goebbels at least felt the need to respond to Einstein's behavior. Reacting to Einstein's official resignation from the Prussian Academy of Sciences, the Academy was pressured into a "good riddance" press release that decried Einstein's recent anti-Nazi statements, and the Propaganda Minister himself remarked in a speech that:
We had allowed international Jewry to be shown a goodwill it did not at all deserve. And what was the Jews' thanks? At home they repented, while out in the world they kindled a lie and atrocity campaign which exceeds even that of the world war. The Jews in Germany can thank the refugees like Einstein for the fact that they themselves are today—completely legitimately and legally—being called to account.
During the infamous German book burnings, Einstein's texts would be included as part of the conflagration, and further, while I am hardly the person to discuss it (/u/restricteddata I believe has before but I'm not finding the post), there was even movement with Germany to 'de-Judasize' physics, creating a 'Deutsche Physik' (or Aryan Physics), although it can hardly be said to have been a resounding success as I understand it (nor was Hitler particularly involved in the movement).
Hi, friends,
Welcome to /r/AskAllAboutHitler! Congratulations, you can now add "Albert Einstein's U.S. citizenship" to the list of things you are simply must know Hitler's opinion of: Roman emperors, Greek philosophers, Napoleon, Anglo-Saxon England, regular England, Ireland, historical monument desecration, the Holy Roman Empire, Denmark, Spanish people (not Spain, though), Aryans in the Indian sense, modern Indians, Asians, gingers, Afro-Germans, African-Americans in Germany, Slavs, Muslims, Jews (...seriously?), Ethiopian Jews, North African Jews, Wagner, Charlie Chaplin, Disney movies, pop music, religion, different religions, Christianity, Shinto, Zionism, Freemasonry, the occult, aliens, drugs, alcohol, gun ownership, Japanese wartime atrocities, Pearl Harbor, the Munich Agreement, Spanish neutrality, Churchill, Roosevelt, Roosevelt's death, Goebbels, potential successors, traditional German food, and of course, masturbation.
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