Agree with kaarlowe regarding the <60k monthly lease C208 being the better aircraft with grimsleeper's suggestion to evaluate aircraft based on Cost per Available Seat Mile (CASM). With that in mind, if you really want the aircraft that consumes less fuel in the <60k monthly lease range, I'd suggest not operating the F406 beyond 399 miles. You'll get a decent return on your investment if you don't push the 406 beyond that. Actually, I'd suggest you not push any of the aircraft in that <60k monthly lease range beyond 399 miles. Btw...if you want to be somewhat realistic, I believe scheduled air carriers (at least in the U.S.) are required to have at least two pilots onboard, which eliminates the C208 from fleet consideration. By the numbers, the Dornier 228 would be the most efficient aircraft, CASM-wise, under 60k monthly lease, with two pilots...then the Beriev 32 (again, based on CASM). By AE numbers, if you factor out a 45-minute fuel reserve, and configure the D0-228 and Be-32 at max seating, their respective max operating ranges would be 351 and 326 miles, anyway.