In advance of the First American Army, September 12 to November 11, 1918, the flying personnel of its observation squadrons had to contend with new conditions which made previous experience and training practically useless. The squadron of the writer was forced to learn by experience tactics to be used. During the campaigns these crystallized into more or less well-defined lines of operation, and believing them to be different from or more perfected than previous training instructions, he submits them for record. The methods given are a result of these missions, and either directly illustrated by or clearly apparent from them. In addition is added a chapter on organization of missions with a few practices which are believed to be desirable from experience.