The Royal Aircraft Factory B.E.3 was a British single-engine biplane aircraft produced during World War I. It was developed as an improvement over the earlier B.E.2, which was the first aircraft specifically designed for military reconnaissance purposes.

The B.E.3 entered service with the Royal Flying Corps (RFC) in 1914, and it saw limited use in the early years of the war. It was primarily used for reconnaissance and artillery spotting missions, although it was also used for bombing and ground attack missions later in the war.

The B.E.3 was an improved version of the B.E.2, with a more powerful engine and a redesigned wing structure that provided better stability and control. It was armed with a single Lewis machine gun, which was mounted on a flexible mount and operated by the observer in the rear cockpit.

The B.E.3 was known for its excellent stability and its ability to fly at high altitudes, which made it well-suited for reconnaissance missions. However, it was also known for being relatively slow and vulnerable to attack, particularly later in the war when it faced more advanced German fighters.

Despite its limitations, the B.E.3 remained an important aircraft throughout World War I, and it played a key role in the development of aerial reconnaissance and military aviation in general. It was eventually replaced by newer and more advanced aircraft, such as the Bristol F.2 Fighter, but it remained in service in various roles throughout the war.