American planes realistically have some of the most powerful armaments in the game, considering that their fighters get a 37mm cannon relatively early in game. That said their maneuverability is a problem, and having someone watching your back is a must to prevent being an easy kill for a more agile aircraft.
After WWI, the American people wanted things to return to the way they used to be. But the U.S had already taken the responsibility as a world power. The United States Navy continued to build new and stronger ships. It also continued to develop the Japanese invention of carrier aviation. The Army Air Corp developed America's first all-metal monoplane fighter, the P-26, in the early 1930s.
The world's first all-metal monoplane fighter was a German invention in 1915. Its bomber force saw major advancements just before the war began in 1939 with the introduction of advanced versions of the B-17, the plane that would prove so crucial in the air war over Europe. All the while, many Americans saw Germany's rearming and Japan's invasion of Manchuria as a problem for Europe and her colonies. Many called FDR a war monger when he allowed military supplies to be sent to England and several different nations in the Pacific. This was the beginning of America's war-long status of chief manufacturer for the Allies' war machine.
Then, on December 7, 1941, 6 heavy Japanese carriers launched an attack involving more than 350 planes on Pearl Harbor, in the US territory of Hawaii. Many Battleships were sunk or damaged. By a stroke of luck, all the carriers were out of port at the time. Within half a year, it was obvious that carriers would be much more important than battleships in this war. Soon, Germany declared war on the United States and America was in the fight 3 years after the war's start, and all its abandoned factories roared to life and began mass producing devices of destruction. By 1944 it assisted in the invasion of Normandy and the liberation of France, while continuing to gain air supremacy in the pacific after several critical battles. The P-80 jet fighter didn't really see combat, but it was a direct result of the war.