The Lepere 2-seated fighter was quickly followed by two other Lepere models--one of them, known as the Lepere C-21, being armored, and driven by a Bugatti engine, and the other a triplane driven by two Liberty engines and designed to be a day bomber. Then the first American designed single-seat pursuit planes began making their appearance--the Thomas-Morse pursuit plane, its 164 miles an hour at ground level, making it the fastest airplane ever tested by our Government, if it were not the speediest plane ever built; the Ordnance Engineering Corporation's Scout, an advanced training plane; and several others. In two-seater fighting planes there was the Loening monoplane, an extremely swift and advanced type. There were several other new two-seaters designed experimentally in some instances and some of them giving brilliant promise. [Illustration: THE LOENING MONOPLANE. This is one of the new distinctively American planes.] [Illustration: THE LOENING TWO-PLACE PURSUIT PLANE.] Perhaps the severest and most exacting critic of aviation material is the aviator who has to fly the plane and fight with the equipment at the front. Brig. Gen. William Mitchell, then a colonel, was sent to France in 1917. He became in succession chief of the air service of the First Army Corps, chief of the air service of the First Army, and finally chief of the air service of the American group of armies in France. He commanded the aerial operations at the reduction of the St. Mihiel salient, where he gained the distinction of having commanded more airplanes in action than were ever assembled before under a single command. At St. Mihiel there were 1,200 allied planes in action, including, with our own, French, English, and Italian planes. Gen. Mitchell, therefore, is a high authority as to the relative merits of air equipment from the airman's standpoint. In the spring of 1919, after a thorough investigation of the latest types of American planes and aerial equipment at the Wilbur Wright Field at Dayton, he sent to the Director of Air Service, Washington, D. C., the following telegram under date of April 20, 1919: I recommend the following airplanes in the numbers given be purchased at once: 100 Lepere 2-place corps observation, 50 Loening 2-place pursuit, 100 Ordnance Engineering Corporation 1-place pursuit, 100 Thomas-Morse 1-place pursuit, 50 USD9-A day bombardment, 700 additional Hispano-Suiza 300-horsepower engines, 2,000 parachutes. All of the above types are the equal of or better than anything in Europe. MITCHELL.