Two teams led by Boeing Research & Technology completed 18-month studies and submitted their findings to NASA under a program called N+3, which denotes three generations beyond the current transport fleet. The Boeing supersonic team, which includes BR&T, BCA, Pratt & Whitney, Rolls Royce, General Electric, Georgia Tech, Wyle and M4 Engineering, has recommended to NASA a fixed wing configuration (nicknamed Icon II) with V-tails and upper surface engines as the technology reference concept plane for N+3. The Icon II concept can carry 120 passengers in a two-class, single-aisle interior, and can cruise at Mach 1.6 to Mach 1.8 with a range of about 5,000 nautical miles.