Kurt Welter (25 February 1916 – 7 March 1949) was a German "Luftwaffe" fighter ace and the most successful "Jet Expert" of World War II.
 A flying ace or fighter ace is a military aviator credited with shooting down five or more enemy aircraft during aerial combat.
 He claimed a total of 63 aerial victories—that is, 63 aerial combat encounters resulting in the destruction of the enemy aircraft—achieved in 93 combat missions.
 He recorded 56 victories at night, including 33 Mosquitos, and scored more aerial victories from a jet fighter aircraft than anyone else in World War II and possibly in aviation history.
 However this score is a matter of controversy; research of Royal Air Force losses suggests Welter overclaimed Mosquito victories considerably.
Walter Nowotny (7 December 1920 – 8 November 1944) was an Austrian-born fighter ace of the Luftwaffe in World War II.
 He is credited with 258 aerial victories—that is, 258 aerial combat encounters resulting in the destruction of the enemy aircraft—in 442 combat missions.
 Nowotny achieved 255 of these victories on the Eastern Front and three while flying one of the first jet fighters, the Messerschmitt Me 262, in the Defense of the Reich.
 He scored most of his victories in the Focke-Wulf Fw 190, and approximately 50 in the Messerschmitt Bf 109.
"Jagdgeschwader" 54 (JG 54) was a Luftwaffe fighter wing during the Second World War, which was the second highest scoring wing of all time, JG 52 being the highest.
 JG 54 flew on the Eastern Front claiming over 9,600 aircraft shot down, with pilots such as Walter Nowotny, Otto Kittel, Hans-Ekkehard Bob, Max-Hellmuth Ostermann and Hannes Trautloft being termed "Experten".
Hans Beißwenger (8 November 1916 – 6 March 1943) was a German Luftwaffe fighter ace and recipient of the Knight's Cross of the Iron Cross with Oak Leaves during World War II.
 A flying ace or fighter ace is a military aviator credited with shooting down five or more enemy aircraft during aerial combat.
 In 500 combat missions, Beißwenger was credited with 152 victories, making him the 34th highest-scoring Luftwaffe fighter pilot of World War II.
 He was "ace-in-a-day" twice, shooting down five aircraft on a single day.
 He claimed all but one of his victories over the Eastern Front.
 He was reported missing in action in March 1943.
Friedrich Wachowiak (13 February 1920 – 16 July 1944) was a former German Luftwaffe fighter 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.
 Wachowiak served with Jagdgeschwader 52 (JG 52—52nd Fighter Wing) and Jagdgeschwader 3 (JG 3—3rd Fighter Wing) and gained his first victories against the Royal Air Force in 1940.
 At the end of 1941 he received his 20th victory and the 40th was in March 1942.
 His first Soviet victory was on 1 May 1942.
 On 7 May 1942 he reported his 62nd and on 29 November 1942 the 86th victory.
 1943/1944 he was temporary a fighter flight trainer and came back to the front in May 1944 with the JG 52 over Normandy.
Günther Scholz (December 8, 1911 – October 24, 2014) was a fighter ace in the Luftwaffe, and was the last surviving member of the Condor Legion during the Spanish Civil War.
 He later participated in the Battle of Britain and commanded Jagdgeschwader 54 during World War II.
 He had accumulated at least 33 "kills" during his time of service.
 His memoirs are documented in the book "In the Skies over Europe".
Stanisław Skalski {'1': ", '2': ", '3': ", '4': "} (27 November 1915 – 12 November 2004) was a Polish fighter ace of the Polish Air Force in World War II, later rising to the rank of Brigadier General.
 Skalski was the top Polish fighter ace of the war and the first Allied fighter ace of the war, credited, according to official lists, with 18 victories and two probable.
 Some sources, including Skalski himself, give a number of 22 victories.
"Jagdgeschwader" 76 (JG 76) was a Luftwaffe fighter-wing of World War II.
 JG 76 was first formed in 1939 in Wien-Aspern with only I. "Gruppe" (1st group).
 The "Geschwader" was renamed II.
/Jagdgeschwader 54 on 4 July 1940.
Hubertus von Bonin (born 3 August 1911, Potsdam – 15 December 1943) was a German Second World War fighter ace who served in the "Luftwaffe".
 A flying or fighter ace is a military aviator credited with shooting down five or more enemy aircraft during aerial combat.
 Bonin is credited with shooting down 77 enemy aircraft.
 The majority of his victories were claimed over the Eastern Front.
 He also claimed four victories in Spain during the civil war.
 His commands included "Geschwaderkommodore" of Jagdgeschwader 54 (JG 54—54th Fighter Wing).
Werner Schröer (12 February 1918 – 10 February 1985) was a German World War II fighter ace who served in the "Luftwaffe" from 1937, initially as a member of the ground staff, until the end of World War II in Europe on 8 May 1945, by which time he had reached the highest ranks of combat leadership.
 A flying ace or fighter ace is a military aviator credited with shooting down five or more enemy aircraft during aerial combat.
 Schröer was also a recipient of the Knight's Cross of the Iron Cross with Oak Leaves and Swords.
 The Knight's Cross of the Iron Cross and its higher grade Oak Leaves and Swords was awarded to recognise extreme battlefield bravery or successful military leadership.
 For the fighter pilots, the grades of the Knight's Cross were also a quantifiable measure of their success and skill.
 Werner Schröer was the second most successful claimant of air victories after Hans-Joachim Marseille in the Mediterranean.

Question: Jagdgeschwader 54 was piloted by the fighter ace of what nationality during World War II?
Answer: Austria