In 1939 not so good, in 1940 not too bad, 1941 was certainly a good year, 1942 and after was an avalanche.
1939 = 5,856 aircraft.
1940 = 12,804 aircraft.
1941 = 26,277 aircraft.
1942 = 47,836 aircraft.
1943 = 85,898 aircraft.
1944 = 96,318 aircraft.
Now what counts as an airplane is certainly up for debate. From Wiki
"The need for new pilots created an insatiable appetite for the Cub. In 1940, the year before the United States' entry into the war, 3,016 Cubs had been built; wartime demands soon increased that production rate to one Cub being built every 20 minutes"
Please note that that figure of 3,016 Piper cubs is for the J-3 model. The J-4 coupe (side by side seating) racked up another 1200 and some odd planes before the war and the J-5 (pilot in front and two passengers in the back) racked up at least 700 prewar.
Add in all the Taylorcraft, Aeronca and other small/light aircraft and the total gets rather large even if they are hardly warplanes.
depending on what is counted the numbers for 1939/40 are all over the place.
1940 actually saw about 3,064 combat and large transports built.
But the small aircraft were used by thousands in flying schools.