..speed limit?

The 757 is a low-wing cantilever monoplane with a conventional tail unit featuring a single fin and rudder. Each wing features a supercritical cross-section and is equipped with five-panel leading edge slats, single- and double-slotted flaps, an outboard aileron, and six spoilers. The wings are largely identical across all 757 variants, swept at 25 degrees, and optimized for a cruising speed of Mach 0.8 (533 mph or 858 km/h). The reduced wing sweep eliminates the need for inboard ailerons, yet incurs little drag penalty on short and medium length routes, during which most of the flight is spent climbing or descending.The airframe further incorporates carbon-fiber reinforced plastic wing surfaces, Kevlar fairings and access panels, plus improved aluminum alloys, which together reduce overall weight by 2,100 pounds (950 kg).
To distribute the aircraft's weight on the ground, the 757 has a retractable tricycle landing gear with four wheels on each main gear and two for the nose gear. The landing gear was purposely designed to be taller than the company's previous narrow-body aircraft in order to provide ground clearance for stretched models. In 1982, the 757-200 became the first subsonic jetliner to offer carbon brakes as a factory option, supplied by Dunlop. The stretched 757-300 features a retractable tailskid on its aft fuselage to prevent damage if the tail section contacts the runway surface during takeoff.