by the Air Service of the United States Army between May 15 and August 10, 1918, a daily run between Washington, D.C., and New York City with an intermediate stop in Philadelphia, Pennsylvania. The operation was put together in ten days by Major Reuben H. Fleet, the executive officer for flying training of the Division of Military Aeronautics, and managed by Captain Benjamin B. Lipsner, a non-flyer. Starting with six converted Curtiss JN-4HM "Jennies", two of which were destroyed in crashes, and later using Curtiss R-4LMs, in 76 days of operations Air Service pilots moved 20 tons of mail without a single fatality or serious injury, achieving a 74% completion rate of flights during the summer thunderstorm season. Air mail operations by the U.S. Post Office began in August 1918 under Lipsner, who resigned from the Army on July 13 to take the post. Lipsner procured Standard JR-1B biplanes specially modified to carry the mail with twice the range of the military mailplanes, the first civil aircraft built to U.S. government specifications. For nine years, using mostly war-surplus de Havilland DH.4 biplanes, the Post Office built and flew a nationwide network. In the beginning the work was extremely dangerous; of the initial 40 pilots, three died in crashes in 1919 and nine more in 1920. It was 1922 before an entire year ensued without a fatal crash. As safety and capability grew, daytime-only operations gave way to flying at night, assisted by airway beacons and lighted emergency landing fields. Regular transcontinental air mail delivery began in 1924. In 1925, to encourage commercial aviation, the Kelly Act (also known as the Air Mail Act of 1925) authorized the Post Office Department to contract with private airlines for feeder routes into the main transcontinental system. The first commercial air mail flight was on the route CAM (Contract Air Mail) No. 5 from Pasco, Washington, to Elko, Nevada, on April 6, 1926. By 1927 the transition had been completed to entirely commercial transport of mail, and by 1929 45 airlines were involved in mail delivery at a cost per mile of $1.10. Most were small, under-capitalized companies flying short routes and old equipment. Subsidies for carrying mail exceeded the cost of the mail itself, and some carriers abused their contracts by flooding the system with junk mail at 100% profit or hauling heavy freight as air mail. Historian Oliver E. Allen, in his