The Vickers E.S.1 (Experimental Scout 1) was a British biplane fighter aircraft built by Vickers Limited in 1917 during World War I. It was designed as an experimental aircraft to test new technologies and design features that could be incorporated into future fighter aircraft.

The Vickers E.S.1 was a single-seat biplane with a wooden frame and fabric covering. It was powered by a 110-horsepower Le Rhone rotary engine and had a top speed of around 120 miles per hour (190 kilometers per hour) and a ceiling of around 20,000 feet (6,100 meters). The aircraft was armed with two synchronized Vickers machine guns mounted on the fuselage.

The most notable feature of the E.S.1 was its design, which incorporated a number of advanced features for the time, including a monocoque fuselage (a single, self-supporting shell), a streamlined cowling around the engine, and a retractable undercarriage. The aircraft also had a relatively small wing area, which gave it a high power-to-weight ratio and made it extremely maneuverable.

Despite its advanced design, the Vickers E.S.1 was not put into production, and only two examples were built. However, the aircraft did serve as a testbed for a number of innovative design features that were later incorporated into other fighter aircraft of the period.

Overall, the Vickers E.S.1 was an important experimental aircraft in the history of aviation, and helped pave the way for the development of more advanced and effective fighter aircraft in the years following World War I.