To air craftsmen, Orville Wright’s reaction served to emphasize the fact that all of us had been sucked up by the slipstream of our own propellers and whirled about like withered leaves or bits of waste paper. Yet underneath we knew that this apparently confused and wasteful process had accelerated progress. As engineers, we realized that when an airplane is earthbound with its engine revving up, the engine’s power is all wasted in noise and heat. In free flight, on the other hand, an airscrew converts upward of 80 per cent of its power into “effective forward thrust,” leaving but 20 per cent as “slip.” Our slipstream is therefore an efficient machine measured by any standard. To permit aviation to soar to new heights we must cast off its shackles. To this end we must needs understand its fundamental import. My own thinking along this line began one November day in 1918, while watching the vaunted German High Seas Fleet surrender to the famed British Grand Fleet. At that time I was chief engineer of the battleship _Arkansas_, one of five American vessels that comprised Adm. Hugh Rodman’s Sixth Battle Squadron of Sir David Beatty’s Grand Fleet. Beatty had a secret weapon, a force of aircraft carriers. Some observers ascribed the German surrender to knowledge of this fact, yet Beatty himself realized that victory had been won, not by the ironclads which, since Jutland had not come into decisive action, but by the battered nine-knot tramps, the doughty drifters and trawlers, the troop-carrying liners and the wallowing tankers—merchantmen that had been keeping the life blood coursing through the Empire’s veins. Watching this triumph of sea power, even as the shadow of an airplane flitted across the gun turrets of the Grand Fleet, I had sought to draw an analogy between sea power and air power but had dismissed the idea because there had been no such thing then as commercial air transport. The war over, Rear Adm. William Adger Moffett, founder and first Chief of the Navy Bureau of Aeronautics, called me in from general service to specialize in aircraft engine production and, incidentally, to lend him a hand in his fight with Brig. Gen. William Mitchell, Assistant Chief, U.S. Army Air Service. This conflict between belligerent giants was more than a revival of the old Army-Navy Game. To the admiral, an inspiring leader and astute politician, the task was to prevent Mitchell, a brilliant pilot and ardent air enthusiast, from monopolizing all aviation—commercial, naval, and military—under an administrative setup resembling the new British Air Ministry. This separate and independent department, in the opinion of the admiral, had already begun to wreck British naval aviation and thus undermine British sea power.