It helps to keep two aircraft straight. The Folland Gnat is the original British design: the single-seat Gnat F.1 fighter and the two-seat Gnat T.1 RAF trainer. India licence-built the single-seat fighter through Hindustan Aeronautics (HAL) and flew it in the 1965 and 1971 wars.

O HAL Ajeet (Sanskrit for “invincible” or “unconquerable”) is India’s own improved development of that fighter — sometimes called the Gnat II. It first flew on 6 March 1975 and entered service in 1977. The key change was a redesigned “wet” wing carrying fuel inside the structure, which freed up the underwing pylons for weapons; it also gained better avionics, improved hydraulics and a zero-zero ejection seat. Around 90 Ajeets were built or converted, and the type served until 1991. So: Gnat = the British original and its Indian licence copies; Ajeet = the later, distinctly Indian evolution.

The Gnat’s combat advantage was largely a function of its size. A pilot chasing one had a genuinely small target to track and shoot, and the Gnat’s low wing loading let it turn tightly. Indian pilots in 1965 found they could bleed a Sabre’s energy in a turning fight and reverse the geometry. The trade-offs were real too — short range, a small fuel load, and early reliability gremlins in the hydraulics and longitudinal control — but in a close, visual dogfight the little Folland was a difficult opponent.

Before the BAe Hawk became synonymous with the Red Arrows, the team flew the Gnat. The RAF had formed several Gnat-equipped display teams in the early 1960s — most notably the Yellowjacks in 1964, flying yellow-painted trainers. From these grew the Red Arrows, officially formed in 1964 and debuting in the 1965 season in their now-iconic red. They flew the Gnat until the end of the 1979 season, converting to the Hawk for 1980. For a generation of British air-show crowds, the Red Arrows were the Gnat.

Low cost was the Gnat’s entire reason for being — Petter pitched it explicitly as a fighter a smaller air force could afford in numbers, and it was far cheaper to buy and run than a Hunter or Lightning. But the type was a 1950s–60s government and licence product, never openly traded on a dollar market, so a firm flyaway unit price and a credible cost-per-flight-hour simply do not exist in the public record. Any precise figure you see is an estimate. What is well documented is the intent: minimum size, minimum systems, minimum cost.