Supplies have to ultimately get from their source
Supplies have to ultimately get from their source, to a market and in the end, the consumer. Early manufacturers had very limited means to get their products from their warehouses to the final consumer. Horse drawn wagons and carts transported goods to merchants along established routes and seafaring ships transported goods between countries on a global scale. At the time, time was not considered a factor and many customers lived with this as a fact of life along with deliveries on the scale of months to years as not unusual. Eventually, wagons gave way to barges and trains which sped up the process between major hubs and ships grew in size to permit the transportation of more products between countries. With increased capacity and trains running on a prescribed schedules, product deliveries were reduced from months to weeks. The early advent of the airplane did not resolve this issue as many planes were small and light weight. With the onset of World War II, larger planes were developed as a strategic measure to deliver troops, ordinance and supplies to the battlefield; however due to their size and total numbers available, many supplies were given a lower priority and still transported mainly using ground based equipment. It was not until after the end of World War II when the allied forces would receive their trial of fire after the Soviets, who controlled most of Germany, conducted a blockade of the city of Berlin cutting off all ground access. The allied forces needed to take immediate action to prevent the starvation of the city.