There are several other items--such as the steel landing chassis, the steering instruments and the upholstery--which we must have on hand before we are ready to commence the work of assembling. When all have been procured the happy task begins. The wings are put in place, and carefully secured by wires and supporting struts. The steering apparatus is installed, the cushioned seats are placed in the cockpits, the fuselage is mounted on the wheeled chassis, and finally when all is complete the big bird is sent out for its first test flight. If there is any one way in which the airplane of to-day differs radically in its process of manufacture from the airplane of a few years ago it is in this: that it is a _tested_ machine. The greatest enemy of the aviator was and always will be, not so much the bullets of an enemy as the hidden flaw in his machine's construction, which makes it "go back on him" when he least expects. The pioneer aviator built himself what he considered a "strong airplane," but when he attempted flight under weather conditions not so favorable as those on which he had counted, some untested part gave way. So in the early days there were many tragedies. To-day, the airplane has become a safe mount indeed, for not only is the finished machine tried out before it is put into use, but each separate part is subjected to the most exacting series of tests. If it does not bear up under at least six times the strain it will ever be called on to endure in flight, it is rejected as unfit. That is the reason the aviator of to-day dares to perform all the marvelous tricks in the air of which we read. Back of the stories of heroism and daring that have come from the battle line during the Great War, and back of the great commercial feats and enterprises that are being planned for the near future, we must not lose sight of the remarkable progress in airplane manufacture and the careful painstaking research and experiment that have resulted in greater safety in the air. Of course it was the war that spurred every one on to do his best in the design and construction of airplanes. Before that time England and America had made very poor showings, and France, although deeply interested in aviation, had nothing in the way of a flying machine that would not seem ancient compared with the airplanes of the present time.