Why 1939 was too early for Pearl Harbor's air strike

Could a Pearl Harbor-style carrier strike have been delivered in 1939?

No. Aircraft numbers and the rapid development of American and Japanese naval aviation during the following eighteen months to two years changed what was possible.

The aircraft numbers available in 1939 would not have supported an attack on the scale of Pearl Harbor. American and Japanese naval aviation changed rapidly during the following eighteen months to two years. Japan was consciously preparing for war during that interval, while American preparations were less explicitly understood in those terms. Moving the comparison back to 1939 therefore changes the balance between carrier aviation and battleship striking power.