ABSTRACT
Since its formal inception with the passage of the Air Mail Act in 1925, the air transportation system has experienced tremendous growth. Air transportation has evolved from a luxury to an important and necessary part of the economy and of daily life. Air transportation infl uences how business is conducted, companies are run, and vacations are taken. Because of air transportation, it is possible to travel or deliver products to almost anywhere in the United States within 24 hours. This ability, coupled with advances in communication technology, has increased the business and social clock cycle. Figure 2.1 shows the signifi cant growth of cargo shipments and passenger travel since 1935. Revenue passenger miles (RPMs) is the number of paying passengers multiplied by the number of miles traveled and revenue ton miles (RTMs) is the amount of cargo paid to be shipped multiplied by the distance traveled. In 2004, the air transportation system handled over 70 thousand fl ights and 146 billion pounds of cargo per day [1].
