Aero L - 29 Delfín The Aero L - 29 Delfín ( , NATO reporting name : Maya ) is a military jet trainer aircraft that became the standard jet trainer for the air forces of Warsaw Pact nations in the 1960s . It was Czechoslovakia ' s first locally designed and built jet aircraft . Design and development . In the late 1950s , the Soviet Air Force was seeking a jet - powered replacement for its fleet of piston - engined trainers , and this requirement was soon broadened to finding a trainer aircraft that could be adopted in common by Eastern Bloc air force s . Aero ' s response , the prototype XL - 29 designed by Z . Rublič and K . Tomáš first flew on 5 April 1959 , powered by a British Bristol Siddeley Viper engine . The second prototype was powered by the Czech - designed M701 engine , which was used in all subsequent aircraft . The basic design concept was to produce a straightforward , easy - to - build and operate aircraft . Simplicity and ruggedness were stressed with manual flight controls , large flaps and the incorporation of perforated airbrakes on the fuselage sides providing stable and docile flight characteristics , leading to an enviable safety record for the type . The sturdy L - 29 was able to operate from grass , sand or unprepared fields . Both student pilot and instructor had ejection seats , and were positioned in tandem , under separate canopies with a slightly raised instructor position . In 1961 , the L - 29 was evaluated against the PZL TS - 11 Iskra and Yakovlev Yak - 30 and emerged the winner . Poland chose to pursue the development of the TS - 11 Iskra anyway , but all other Warsaw Pact countries adopted the Delfin under the agreements of COMECON . Production began April 1963 and continued for 11 years , with 3 , 600 eventually built until 1974 . A dedicated , single - seat , aerobatic version was developed as the L - 29A " Akrobat " . A reconnaissance version with nose - mounted cameras was built as the L - 29R . Operational history . The Delfin served in basic , intermediate and weapons training roles . For this latter mission , they were equipped with hardpoint s to carry gunpods , bombs or rockets , and thus armed , Egyptian L - 29s were sent into combat against Israeli tanks during the Yom Kippur War . The L - 29 was supplanted in the inventory of many of its operators by the Aero L - 39 Albatros . More than 2 , 000 L - 29s were supplied to the Soviet Air Force , acquiring the NATO reporting name " Maya . " L - 29 ' s , along with the newer L - 39 , were used extensively in ground attack missions in the Nagorno - Karabakh War by Azeri forces . At least 14 were shot down by Armenian air - defences . As a trainer , the L - 29 enabled air forces to adopt an " all - through " training on jet aircraft , replacing earlier piston - engined types . On July 16 , 1975 , a Czechoslovak Air Force L - 29 shot down a Polish civilian biplane piloted by Dionizy Bielański that was attempting to defect to the West . On October 2 , 2007 , an unmodified L - 29 was used for the world ’ s first jet flight powered solely by 100 % biodiesel fuel . Pilots Carol Sugars and Douglas Rodante flew their Delphin Jet from Stead Airport , Reno , Nevada to Leesburg International Airport , Leesburg , Florida in order to promote environmentally friendly fuels in aviation . From September 10 to September 14 , 2008 , two L - 29s took first and second place at the Reno Air Races . Both L - 29s consistently posted laps at or above 500 miles per hour . Former Astronaut Curt Brown took first place in " Viper , " followed by Red Bull racer Mike Mangold in " Euroburner . " Russia says it destroyed two Georgian L - 29s during the 2008 South Ossetia war .