This report is divided into three parts. The first two of these describe the A-60, Mach 2.2 airliner and the A-62, Mach 3.0 airliner design studies respectively. Apart from the different cruise speeds these two aircraft were designed to meet the same basic requirements and the third part of the report is a comparison of them. The Mach 2.2 design was based upon the use of a slender, integrated, delta layout with six turbojet engines buried in the rear fuselage. It was intended to carry up to 120 passengers over transatlantic ranges. Although the chosen engine installation enabled a compact aircraft to be designed it did introduce severe structural and installation difficulties. A canard delta arrangement was proposed for the Mach 3.0 aircraft. Drooping of the wing tips for supersonic flight was found to confer important stability advantages without introducing an unacceptable weight penalty. The steel structure was designed around the use of both corrugated reinforced and honeycomb sandwich skins, the former being preferable. An interesting feature was the choice of a sealed, cryogenic, environmental control system. This was found to be very attractive but as it proved to be somewhat heavier than anticipated it is suggested that a good compromise could be obtained by using a more conventional system for subsonic flight phases. The major conclusion from the comparison between the two study aircraft was that in many respects there is very little to choose between them. However the Mach 2.2 aircraft represents a more logical step from existing airliner designs and presents fewer materials problems. As it is comparable economically it represents a better choice for a first generation supersonic design.