I have trouble finding hard data on this too. Americans generally gave weapons to it's allies Britain and France, and later the Soviet Union as the war intensified. The U.S did actively trade with Nazi Germany before the war, but I don't think weapons were a large part of this.
It should be noted that before the U.S got directly involved in the war, many if not most Americans weren't sure which side they were on. Much of America was anti-communist, and so was Hitler and the other fascist nations of Europe. Hitler was fighting Stalin and Americans loathed Stalin. Americans may not have been very fond of fascism, but it seemed more compatible with capitalism than communism. The U.S was more against communism. Truth be told, anti-fascist sentiments weren't especially strong in the U.S during the 1920s and 1930s, except on the far left(in fact, since all communists were opposed to fascism, people who were very opposed to fascism were sometimes suspected of being communists).
Many Americans were also distrustful of Jews, although American antisemitism always paled in comparison to European antisemitism. The U.S was still a very racist country during the 40s and 50s, so Hitler's racism wasn't exactly totally out of the ordinary to most Americans back then.
