Alexander Nikolaievich Prokofiev de Seversky (Russian: Алекса́ндр Никола́евич Проко́фьев-Се́верский) (June 7, 1894 (N.S.) – August 24, 1974) was a Russian-American aviation pioneer, inventor, and influential advocate of strategic air power.

Of noble Russian parentage, Seversky was born in Tiflis, Russian Empire (now Tbilisi, Georgia). He entered a military school at age 10. Seversky's father was one of the first Russian aviators to own an aircraft (a modified Blériot XI built by Mikheil Grigorashvili) and by the age of 14, when Seversky entered the Imperial Russian Naval Academy, his father had already taught him how to fly. Graduating in 1914 with an engineering degree, Lieutenant Seversky was serving at sea with a destroyer flotilla when World War I began.^{[better source needed]}

Seversky was selected for duty as a naval aviator, transferring to the Military School of Aeronautics at Sebastopol, Crimea. After completing a postgraduate program on aeronautics in 1914–15, he was reassigned as a pilot in the summer of 1915 to an aviation unit in the Baltic Fleet. While stationed in the Gulf of Riga, on his first mission, he attacked a German destroyer but was shot down by enemy anti-aircraft fire before he could drop his bombs. The bombs exploded in the crash, killing his observer and badly wounding Seversky. Doctors amputated his leg below the knee and although he was fitted with an artificial leg, despite his protests, authorities deemed him unfit to return to combat. To prove to his superiors that he could still fly, Seversky appeared unannounced at an air show. Following his impromptu spirited aerial performance, authorities arrested him.

Tsar Nicholas II intervened on his behalf and in July 1916, de Seversky returned to combat duty, downing his first enemy aircraft three days later. In February 1917, he assumed command of the 2nd Naval Fighter Detachment, until he was seriously injured in an accident where a horse-drawn wagon broke his good leg. After serving in Moscow, as the Chief of Pursuit Aviation, Seversky returned to combat duty. On October 14, 1916, he was forced down in enemy territory but made it back to the safety of his own lines. He went on to fly 57 combat missions, shooting down six German aircraft (his claims for 13 victories would make him Russia's third-ranking World War I ace, although the claims are disputed). Lieutenant Seversky was the leading Russian naval ace in the conflict. For his wartime service, Seversky was awarded the Order of St. George (4th class); Order of St. Vladimir (4th class); Order of St. Stanislaus (2nd & 3rd class); Order of St. Anne (2nd; 3rd; and 4th class).

During the 1917 Revolution, Seversky was stationed in St. Petersburg and remained in uniform at the request of the commander-in-chief of the Baltic Fleet. In March 1918, he was selected as an assistant naval attaché in the Russian Naval Aviation Mission to the United States. Seversky departed via Siberia and while in the U.S., decided to remain there rather than return to a Russia torn apart by the Revolution. Settling in Manhattan, he briefly operated a restaurant.

In 1918, Seversky offered his services to the War Department as a pilot. General William Kenly, Chief of the Signal Corps, appointed him as a consulting engineer and test pilot assigned to the Buffalo District of aircraft production. After the Armistice, Seversky became an assistant to air power advocate General Billy Mitchell, aiding him in his push to prove air power's ability to sink battleships. Seversky applied for and received the first patent for air-to-air refueling in 1921. Over the next few years, he would go on to make 364 patent claims, among them the first gyroscopically stabilized bombsight, which Seversky developed with Sperry Gyroscope Company in 1923. After joining the Army Air Corps Reserve, Seversky was commissioned a major in 1928.

Using the $50,000 from the sale of his bombsight to the U. S. Government, Seversky founded the Seversky Aero Corporation in 1923. Concentrating on making aircraft parts and instruments, the small company was unable to survive the stock market crash of 1929. On February 16, 1931, with the backing of Wall Street millionaire Edward Moore and other investors, he resurrected the enterprise as the new Seversky Aircraft Corporation in Long Island, New York. Moving into the former EDO Aircraft Corporation's float plane factory at College Point, Long Island, Seversky's patents were the primary assets of the new company. Resolved to invest in research and design rather than relying on licence-manufacturing, many of Seversky Aircraft's designers were Russian and Georgian engineers, including Chief Engineer Michael Gregor and Alexander Kartveli. Along with Seversky, the designers embarked on an advanced all-metal, multi-place monoplane amphibian, the SEV-3. This ground-breaking design would go on to set numerous speed records at the 1933–1939 National Air Races, often piloted by Seversky himself, who was the company's greatest "pitchman". On September 15, 1935, flying at a speed just over 230 mph, Seversky set a world speed record for piston-engine amphibious aircraft. Seversky also set a transcontinental speed record in 1938.

The SEV-3 was eventually the progenitor of a family of advanced aircraft including the SEV-3XLR and 2-XP (two-place, experimental) fighter, the BT-8 trainer and SEV-1P (single-seat) fighter. The most radical conversion occurred when the fixed-gear SEV-1P was fitted with a rearward retracting main undercarriage to produce the prototype of the successful P-35A fighter series. The Seversky Aircraft design office led by Seversky was responsible for 25 different innovative projects, many of them "still-born" including the "Seversky Super-Clipper", an eight-engine, 250 ft span transoceanic transport and the four-place, tricycle gear "Seversky Executive" high speed personal aircraft. The Sev-S2, virtually identical to the P-35, which was undergoing trials in 1937, dominated the last three Bendix Trophy air races, beginning in 1937 when Frank Fuller won at an average speed of 415.51 km/h.