A great honor has been conferred on me, especially the invitation^which said that I was particularly qualified" to discuss supersonic and transonic aircraft problems. Throughout my ! disertation the emphasis is going to be placed entirely on that word 'problem'. As so ably put by General Craigie quite recently in that "with respect to many of the major problems confronting us today we stand about where the Wright Brothers stood when they were contemplating their first flights some forty odd years ago". Before going into the problems of transonic and supersonic flight I would like to just mention that we have not, nor do we expect to, drop our studies of subsonic flight. Among the subsonic aircraft a great deal of effort is being placed on the development of transport aircraft because of the obvious certainty of global warfare in event of another crisis. In addition to aerodynamics in transport, such items as cold weather operation under adverse flying conditions are receiving much attention. I feel that many of our problems in the design of transonic and supersonic aircraft are fairy ghosts. Ghosts because we have not been able to physically feel the sort of thing our slide rules and small scale test da ta tell us. Remember in high school a lgebra that if some one had set up the equation for Anne's age , her brothers' temperature and the length of the rope the solution for how fast the train was traveling was simple. That is precisely where we are today. We are trying to set up the equation. We are convinced that we will find a solution and that it will be just a matter of time until that solution is found. In fact, reading Sunday Supplements and Comic Magazines indicates that their authors have the solutions. (Figure 1) Some of the terms tha t 'we are sure will fit into the eventual equation for transonic and supersonic flight are: Structures, aerodynamic shapes, control, propulsion installations, materials, armament, and escape provisions. (Figure 2) One of the biggest problems in structural considerations is the increase in loadings with a sizeable decrease in space to absorb these loadings. (Figure 3) As an example the P-80, which travels about fifty percent faster than the old P-40, must absorb approximately 300 percent as much load in approximately the same dimensional space. (Figure 4). In another example, the wing skin thickness in the aircraft of the last World War seldom exceeded 1/16 inch, whereas the skin thicknesses of half inch seem necessary at the present. Wings, which to date have seldom been less than 15 percent thick, must not exceed six percent thick if supersonic speeds are to be realized. (Figure 5) The aerodynamic shape of transonic and supersonic aircraft will probably bear only a vague resemblance to contemporary aircraft. (Figure 6) To cite a few instances, wings and control surfaces will have exceedingly sharp leading edges, in fact it has been suggested that aircraft manufacturers contact makers of razors for their latest on creating sharp edges. (Figure 7) In addition to the sharp leading edges it appears that the transonic airplane will have wings and tail surfaces swept back very much like the paper darts that lunior makes with your favorite sports page . (Figure 8) The wings of