|Born||October 5, 1919|
|Died||22 January 1944(aged 24) M.I.A.|
|Place of birth||Reutlingen|
|Place of death||disappeared near Berdychiv, Ukraine|
|Years of service||? - 1944|
|Awards||Knight's Cross of the Iron Cross|
Otto Gaiser (5 October 1919 – 22 January 1944) was a German Luftwaffe ace and recipient of the Knight's Cross of the Iron Cross during World War II. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership. Gaiser claimed his first kill on 16 March 1943. That day, he shot down a Soviet LaGG-3 fighter near Vyazma. He achieved his 10th victory on 11 July, when he claimed another LaGG-3 shot down. Gaiser claimed 17 victories in August, including five Soviet Il-2 Sturmovik ground-attack aircraft shot down on 14 August (his 24th through 28th victories). On 22 January 1944, Gaiser was last seen in combat with Il-2 Sturmovik fighters near Berdychiv, Ukraine. He has remained missing to this day. It is thought he became a victim of the Soviet ground defences. On 9 June 1944 he was posthumously awarded the Knight's Cross and promoted to Leutnant. Before his death, Gaiser was credited with 66 victories in 380 missions. All his air victories were achieved over the Eastern front and included 21 Il-2 Sturmoviks. In addition he claimed eight unconfirmed victories.
- Ehrenpokal der Luftwaffe (3 April 1944)
- Front Flying Clasp of the Luftwaffe
- Iron Cross (1939)
- 2nd Class
- 1st Class
- German Cross in Gold (28 January 1944)
- Knight's Cross of the Iron Cross on 9 June 1944 as Oberfeldwebel and pilot in 10. / Jagdgeschwader 51
- Obermaier 1989, p. 116.
- Fellgiebel 2000, p. 159.
- Fellgiebel, Walther-Peer (2000) (in German). Die Träger des Ritterkreuzes des Eisernen Kreuzes 1939–1945 – Die Inhaber der höchsten Auszeichnung des Zweiten Weltkrieges aller Wehrmachtsteile [The Bearers of the Knight's Cross of the Iron Cross 1939–1945 — The Owners of the Highest Award of the Second World War of all Wehrmacht Branches]. Friedberg, Germany: Podzun-Pallas. ISBN 978-3-7909-0284-6.
- Obermaier, Ernst (1989) (in German). Die Ritterkreuzträger der Luftwaffe Jagdflieger 1939 – 1945 [The Knight's Cross Bearers of the Luftwaffe Fighter Force 1941 – 1945]. Mainz, Germany: Verlag Dieter Hoffmann. ISBN 978-3-87341-065-7.
- Patzwall, Klaus D.; Scherzer, Veit (2001) (in German). Das Deutsche Kreuz 1941 – 1945 Geschichte und Inhaber Band II [The German Cross 1941 – 1945 History and Recipients Volume 2]. Norderstedt, Germany: Verlag Klaus D. Patzwall. ISBN 978-3-931533-45-8.
- Scherzer, Veit (2007) (in German). Die Ritterkreuzträger 1939–1945 Die Inhaber des Ritterkreuzes des Eisernen Kreuzes 1939 von Heer, Luftwaffe, Kriegsmarine, Waffen-SS, Volkssturm sowie mit Deutschland verbündeter Streitkräfte nach den Unterlagen des Bundesarchives [The Knight's Cross Bearers 1939–1945 The Holders of the Knight's Cross of the Iron Cross 1939 by Army, Air Force, Navy, Waffen-SS, Volkssturm and Allied Forces with Germany According to the Documents of the Federal Archives]. Jena, Germany: Scherzers Miltaer-Verlag. ISBN 978-3-938845-17-2.
- Spick, Mike (1996). Luftwaffe Fighter Aces. New York: Ivy Books. ISBN 978-0-8041-1696-1.