In the United States, the massive mobility requirements during World War II proved that military transport could not meet all the logistical needs that might arise. As a result, the Civil Reserve Air Fleet (CRAF) was developed to use airline capacity to provide maximum airlift support in wartime situations. As a benefit, airlines that commit planes to CRAF are able to receive peacetime government contracts in an amount proportional to the airline's potential wartime mobilization value. This is the basis for most routine military charter flights. The government receives an extremely economical source of emergency capacity as well as reasonable costs for peacetime military transportation.