The strategic location of the United States resulted in the development of two major branches of military aviation — army and naval aviation. Specifications of primary importance were a long operating range, strength and durability, and easy maintenance. The U.S. focused on building high-speed, high-altitude fighters with the ability to carry strike weapons to provide air support to ground and naval forces, and protect friendly high-altitude bombers.
Fighters were mostly designed for vertical mid- to high-altitude combat. The P-51 Mustang and F4U Corsair are perfect representations of the U.S. fighters. Jet-powered aircraft were also employed as fighters to achieve air superiority in mid- and high-altitude combat.
Heavy fighters were designed as strategic aircraft to be rapidly deployed over long distances and perform a wide range of missions. Priority was given to maximum speed and long flight range.