A321neo vs 737-900ER The Boeing 757 occupies a unique market niche at the top end of the narrow-body market. With a two-class capacity of 189 seats, and a 3,900 mile nautical mile range, this aircraft was once a staple of the transcontinental US market and, following the addition of winglets, has carved out a niche on flights from the US East Coast to non-hub European destinations. The 757 has largely been replaced on US trans-con routes by the Boeing 737-800, a somewhat smaller aircraft that is less costly to operate and much less expensive to purchase when both aircraft were in production.