Jonah Goldburg mentions the FDR military buildup of the early and mid 1930s in Liberal Facism. Breakdowns of military expenditures show that military expenditures between 1933 and the outbreak of war in Europe in 1939 were higher than comparable periods of time in the 1920s. The number of military personnel also increased. Military spending between 1933 and the summer of 1939 averaged 1.049 billion dollars per year. A comparable period of the latter half of the 1920s averaged 745 million dollars per year.
The primary beneficiary of these funds was the navy, a choice that seems vindicated by the course of the war that was too come. More than 130 warships were laid down between 1933-39. In 1932, the navy had 132 warships in service - in 1939, 178, a much larger proportion of which were modern. This was also a period when the US was bound by treaty restrictions on naval construction, some of which had been signed in the 1920s.
Now, the Army did languish in this period, but that was pretty much par for the course at the time period. The US didn't really keep a large or modern army around in peacetime, and the US had always entered wars having to build up a new army from scratch, using the small peacetime force as a central corps around which to build the newly mobilized force. Considering that, the army actually did quite well when compared to the 1920s. Total forces were increased, and the reserves were drastically increased in size (243,971 in 1933 vs 334,473 in June of 1939). The Westervelt Board's recommendations on the design of new artillery and AA pieces to be employed in a future war were followed, and an entire family of new arms were trialed and entered production in the 1930s. Congress had killed the early Tank Corps in 1920, crippling the development of armor in America, but even so, trial mechanized fores were formed in the 1930s, and large numbers of prototypes were constructed and experimented with. Although only two tank models, the M1 and M2 Light, actually saw mass production, overall, the US managed to maintain the capability to design modern combat vehicles, and when the spigots were unleashed in late 1939, they were able to come up with some excellent vehicles. Small arms and equipment were also modernized, and most Army units transitioned to motorized formations. The Air Corps also experimented with many types of aircraft, and saw hundreds of modern, metal monoplane bombers, fighters, and patrol aircraft enter service, building the foundation for the solid designs of WW2. As to your specific points - the US Army, serving as an expeditionary force on the attack across vast oceans, had no need for heavy tanks, and quite properly chose not to to adopt any. The newest American fighters and bombers in service in 1941 were comparable to their counterparts fielded by other great powers.