†A Regional Transport Aircraft (RTA) is currently under design and development in India. This paper starts by outlining the need for such an aircraft, and lists the desired design and operating requirements. Results of a conceptual sizing study are presented in which Bombardier’s Q-400 and Antonov’s An-128 aircraft were taken as the baseline for the turboprop and turbofan engined version of the RTA, respectively. These were then resized to meet the specified operating requirements for a 70-seater turboprop and turbofan RTA, using RDS-Student software package. The modified baseline aircraft were then optimized for minimum takeoff gross weight using FLOPS tool developed by NASA LaRC. Sensitivity studies for aircraft with a seating capacity of 50, 70 and 90 were also carried out, which indicate that the takeoff gross weight is strongly influenced by cruising speed and Mach number, and the constraints on takeoff and landing distance.