In 1944 alone, the United States built more planes than the Japanese did from 1939 to 1945. By the end of the war, more than half of all industrial production in the world would take place in the United States.
The welt-beating and slashing machine ensures the welt is parallel to the insole. The outsole is then covered with rubber cement and attached to the upper using a sole-laying machine. The sole is stitched to the rest of the shoe using a lockstitch machine, capable of making 1,000 stitches in a minute.
Leather was the first material used to construct the shoe. However Bowerman soon realized that he could reduce the weight of the shoe if he changed the material of the shoe's upper to nylon and suede. In 2009, a new design of the Nike Cortez - the Cortez Fly Motion - was released.