After West Point, Lanphier was stationed in the
Panama Canal Zone. His unit was transferred to
France in March 1918 after the US entered
World War I. He served in combat in a machine gun unit and was later transferred to the air corps. He was stationed at
Post Field,
Fort Sill, later that year until September 1924. He was transferred to
Selfridge Field in
Michigan by November 1924. Later, Lanphier became the commandant of the
1st Pursuit Group at Selfridge Field. Lanphier testified in support of General
Billy Mitchell during Mitchell's 1925
court-martial. Lanphier was the head of the Transcontinental Air Transport Company (September 1928) He also gave a statement in the aftermath of the
Lindbergh kidnapping In 1933, after retiring from the military, he bought
Manhattan's Phoenix Cereal Beverage Company and applied for a license to manufacture
3.2 beer under the brewery's old name of Flanagan-Nay Brewery Corp. The brewery had been operated by mobsters
Owney Madden and
Bill Dwyer since 1925 during
Prohibition. Madden also ordered an airplane and took flight instruction from Lanphier. In 1936, Lanphier headed
The Association for Legalizing American Lotteries, an illegal
lottery. Lanphier and Janet Cobb-Lanphier divorced on March 19, 1936, in
Wayne County, Michigan. In 1938, Lanphier assisted Mary E. Werner, the daughter of former
Summit County, Ohio, coroner Dr. Oscar Hayes, with locating her two children. == World War II and later ==