<div class="htmlview paragraph"><b>A</b>IR transport is an essentially expensive business and operators must study economy at least as much as do other commercial companies to make their business self-supporting.</div> <div class="htmlview paragraph">A commercial-transport airplane must have an even higher degree of efficiency than that of a large military plane and must be in continuous operation so far as possible.</div> <div class="htmlview paragraph">Very high speed may prove to be an expensive luxury; it should be investigated with great care as well as with the present enthusiasm of its sponsors. Speed is not paramount, but profitable load-carrying is. A cheap plane that is inefficient and an efficient plane that is more expensive than it need be are both uneconomical.</div> <div class="htmlview paragraph">Air-transport testing consists not merely in the elimination of defects but in the examination of all the characteristics of the plane to effect the maximum improvement that the design will stand and to discover other characteristics for future development or elimination. The author enlarges upon the foregoing and other economic and testing phases.</div>