The idea of women’s combat aviation regiments came from Marina Raskova, a celebrated Soviet navigator who used her fame — and reported access to Stalin — to win approval on 8 October 1941. She raised three regiments and trained them at Engels, near Saratov. One of them, the 588th Night Bomber Regiment, flew the Po-2 and remained entirely female throughout the war. It flew its first combat missions in June 1942 and, redesignated the 46th Guards “Taman” Regiment in early 1943, went on to fly more than 24,000 combat sorties.

Crews often flew eight to eighteen short sorties a night, each lasting well under an hour, carrying only a light bomb load and frequently no parachutes because of weight and their low altitude. Raskova herself did not survive the war — she was killed on 4 January 1943 crash-landing a Pe-2 — and received the first state funeral of the war. About two dozen women of the regiment became Heroes of the Soviet Union, the most of any Soviet women’s unit. The name “Night Witches” and the glide-and-bomb tactic are historically documented; some individual per-night tallies are best treated as commonly repeated figures rather than exact records.

Intercepting a Po-2 at night was genuinely dangerous for the interceptor. Modern monoplane fighters had high stall speeds; to line up a firing pass on a biplane crawling along near 100–150 km/h, a fighter had to slow so much that it risked stalling and departing controlled flight, especially at low altitude in the dark. The Po-2 could also turn tightly and fly low among terrain where fast aircraft dared not follow. The frequently repeated claim that it flew “below a Messerschmitt’s stall speed” is a simplification, but it captures a real tactical problem that recurred from the Eastern Front in WWII to the jet-age skies over Korea.

Exact totals are uncertain because production spanned decades, multiple factories and several designations (U-2, Po-2 and the Polish CSS-13). Figures in the literature range from roughly 20,000 to as many as 40,000, with about 30,000 the most commonly cited round number. Whatever the precise figure, aviation references consistently describe the Po-2 as the most-produced biplane in history and one of the most-produced aircraft of any kind. Polish licence production of the CSS-13 alone (around 560 aircraft, 1949–1956) extended the type’s manufacturing life into the late 1950s.

The Po-2 was a Soviet state product built across three decades, never sold on an open dollar market, so there is no meaningful flyaway unit price or cost-per-flight-hour figure in the public record. What is clear is the design philosophy: it was engineered to be as cheap and easy to build, maintain and repair as possible — wood, fabric and a simple air-cooled radial, assembled in the tens of thousands. Any precise modern cost you see attached to a Po-2 relates to restoring or operating a rare surviving warbird, not to the original mass-produced aircraft.