Upon its introduction to squadron service with the Czechoslovak Air Force during the latter half of 1935, the B-534 was put to use in the interceptor role.
Initially, the responsibility for pursuit and aerial combat was shared with several other aircraft, including the Avia BA-33L and the Letov Š-31; however, by 1938, the B-534 was the sole type of aircraft in Czech service to be tasked with this role.
By 10 November 1938, a total of 370 B-534 and Bk-534 aircraft in service; additionally, 53 aircraft had been written off as a result of accidents.

On 1 September 1938, less than a month before the Munich Agreement would cause Czechoslovakia to lose 30 per cent of its territory and 34 per cent of its population, 328 B-534s and Bk-534s equipped 21 fighter squadrons of the Czechoslovak Air Force, while other aircraft were assigned to reserve and training squadrons, and deliveries continuing of the final batch of fighters.

On 14 March 1939, Germany forced the partition of Czechoslovakia, with Slovakia being declared as the nominally independent Slovak Republic with Germany annexing the remaining "Czech" part of Czechoslovakia as the Protectorate of Bohemia and Moravia the next day.
The abrupt partition of Czechoslovakia during 1939 prevented any actual combat operations of the B-534 to be conducted by the nation that had produced it.
By then, high performance monoplanes such as the Bf 109 and Britain's leading models – the Hawker Hurricane and Supermarine Spitfire – were raising the bar of fighter/interceptor standards.
The Slovenské vzdušné zbrane (Slovak Air Force) was organised out of the units of the Czechoslovak Air Force that were based in Slovakia at the time of partition, and inherited about 71 B-534s and Bk-534s.

Slovakia had to quickly make use of its newly formed air force, weakened by the departure of many Czech pilots, to defend itself when neighbouring Hungary launched an invasion on 23 March 1939.
During the ensuing combat, a pair of B-534s were shot down by Hungarian anti-aircraft fire while a further four were claimed to have been shot down by Hungarian Fiat CR-32 fighters.
Another Avia was compelled to perform a forced landing behind Hungarian lines and was captured.

During September 1939, Slovakia participated in the German Invasion of Poland; the nation held the aim of regaining territories which had been previously lost to Poland at Munich.
A pair of squadrons of B-534s were assigned to support the invasion.
In the theatre, these were typically used to escort Luftwaffe aircraft, such as the Junkers Ju 87 dive-bomber, on eight missions, during which a pair of B-534s were lost while the downing of a single Polish RWD-8 liaison aircraft was claimed.

The same squadrons fought alongside the elements of the German military in the area of Ukraine during summer 1941.
According to aviation author Josef Krybus, on this front, moral amongst the Slovak pilots was low and no significant victories were achieved during their deployment.
During 1942, one of these squadrons was redeployed to Slovakia to conduct anti-partisan operations.
Over time, a combination of obsolescence, the lack of spare components and the old Czechoslovak air force's proprietary fuel mixture (BiBoLi, or some other mix of ethanol, benzol and petrol) finally relegated the surviving B-534s to performing the trainer role and other secondary duties during 1943.

The training role would have been the last operational service of the B-534s in Slovak colors if not for the Slovak National Uprising of September–October 1944.
The rest of the Slovak air assets did not turn-coat as expected and the leaders of the uprising were faced with using a rag-tag collection of leftover aircraft, including several B-534s stationed at Tri Duby airfield.
On 2 September 1944, Master Sergeant František Cyprich, just after testing a repaired B-534, downed a Junkers Ju 52 transport under Hungarian colors on its way to a base in occupied Poland.
This was at once the first aerial victory for the Uprising and the last recorded biplane fighter air-to-air victory.
As the Slovak Nati
Upon its introduction to squadron service with the Czechoslovak Air Force during the latter half of 1935, the B-534 was put to use in the interceptor role. Initially, the responsibility for pursuit and aerial combat was shared with several other aircraft, including the Avia BA-33L and the Letov Š-31; however, by 1938, the B-534 was the sole type of aircraft in Czech service to be tasked with this role. By 10 November 1938, a total of 370 B-534 and Bk-534 aircraft in service; additionally, 53 aircraft had been written off as a result of accidents.
On 1 September 1938, less than a month before the Munich Agreement would cause Czechoslovakia to lose 30 per cent of its territory and 34 per cent of its population, 328 B-534s and Bk-534s equipped 21 fighter squadrons of the Czechoslovak Air Force, while other aircraft were assigned to reserve and training squadrons, and deliveries continuing of the final batch of fighters.
On 14 March 1939, Germany forced the partition of Czechoslovakia, with Slovakia being declared as the nominally independent Slovak Republic with Germany annexing the remaining "Czech" part of Czechoslovakia as the Protectorate of Bohemia and Moravia the next day. The abrupt partition of Czechoslovakia during 1939 prevented any actual combat operations of the B-534 to be conducted by the nation that had produced it. By then, high performance monoplanes such as the Bf 109 and Britain's leading models – the Hawker Hurricane and Supermarine Spitfire – were raising the bar of fighter/interceptor standards. The Slovenské vzdušné zbrane (Slovak Air Force) was organised out of the units of the Czechoslovak Air Force that were based in Slovakia at the time of partition, and inherited about 71 B-534s and Bk-534s.
Slovakia had to quickly make use of its newly formed air force, weakened by the departure of many Czech pilots, to defend itself when neighbouring Hungary launched an invasion on 23 March 1939. During the ensuing combat, a pair of B-534s were shot down by Hungarian anti-aircraft fire while a further four were claimed to have been shot down by Hungarian Fiat CR-32 fighters. Another Avia was compelled to perform a forced landing behind Hungarian lines and was captured.
During September 1939, Slovakia participated in the German Invasion of Poland; the nation held the aim of regaining territories which had been previously lost to Poland at Munich. A pair of squadrons of B-534s were assigned to support the invasion. In the theatre, these were typically used to escort Luftwaffe aircraft, such as the Junkers Ju 87 dive-bomber, on eight missions, during which a pair of B-534s were lost while the downing of a single Polish RWD-8 liaison aircraft was claimed.
The same squadrons fought alongside the elements of the German military in the area of Ukraine during summer 1941. According to aviation author Josef Krybus, on this front, moral amongst the Slovak pilots was low and no significant victories were achieved during their deployment. During 1942, one of these squadrons was redeployed to Slovakia to conduct anti-partisan operations. Over time, a combination of obsolescence, the lack of spare components and the old Czechoslovak air force's proprietary fuel mixture (BiBoLi, or some other mix of ethanol, benzol and petrol) finally relegated the surviving B-534s to performing the trainer role and other secondary duties during 1943.
The training role would have been the last operational service of the B-534s in Slovak colors if not for the Slovak National Uprising of September–October 1944. The rest of the Slovak air assets did not turn-coat as expected and the leaders of the uprising were faced with using a rag-tag collection of leftover aircraft, including several B-534s stationed at Tri Duby airfield. On 2 September 1944, Master Sergeant František Cyprich, just after testing a repaired B-534, downed a Junkers Ju 52 transport under Hungarian colors on its way to a base in occupied Poland. This was at once the first aerial victory for the Uprising and the last recorded biplane fighter air-to-air victory. As the Slovak Nati
Avia B-534