<P> The Post Office Department played an important intelligence role during World War I, implementing the Espionage and Trading with the Enemy Acts, monitoring foreign mail and acting as counter-espionage to help secure allied victory . </P> <P> On August 12, 1918, the Post Office Department took over airmail service from the United States Army Air Service (USAAS). Assistant Postmaster General, Otto Praeger, appointed Benjamin B. Lipsner to head the civilian - operated Air Mail Service . One of Lipsner's first acts was to hire four pilots, each with at least 1,000 hours' flying experience, paying them an average of $4,000 per year ($65.1 thousand today). The Post Office Department used new Standard JR - 1B biplanes specially modified to carry the mail while the war was still in progress, but following the war operated mostly World War I surplus military de Havilland DH - 4 aircraft . </P> <P> During 1918, the Post Office hired an additional 36 pilots . In its first year of operation, the Post Office completed 1,208 airmail flights with 90 forced landings . Of those, 53 were due to weather and 37 to engine failure . By 1920, the Air Mail service had delivered 49 million letters . Domestic air mail became obsolete in 1975, and international air mail in 1995, when the USPS began transporting First - Class mail by air on a routine basis . </P> <P> The Post Office was one of the first government departments to regulate obscene materials on a national basis . When the U.S. Congress passed the Comstock laws of 1873, it became illegal to send through the U.S. mail any material considered obscene or indecent, or which promoted abortion issues, birth control, or alcohol consumption . </P>

Does a town have to have a post office