With the Allied bombing campaign gaining more and more strength, the demand for a counter was at an all-time high. Other aircraft, like the Me 210, were considered for the role but ultimately a very unique aircraft would be produced: the Bf 109 Z-1 "Zwilling" (German for "twin"). Based on the previous idea of merging two Heinkel He-111 bombers, Messerschmitt engineers fused two Bf 109 airframes together to create one aircraft. Although it had two airframes, one of them would house the pilot, and the other was blocked off, making it a single-seat fighter. The first prototype was called the "Bf 109 Z-0" but was shortly bombed after it was finished. That didn't stop the project, and a year later, the Z-1 was produced and almost ready for tests until it was abruptly cancelled. The Z-1 fused two 109 G-6 airframes and featured high-powered cannons. It was also nicknamed "Sledgehammer" due to its impressive cannon armament.

The Bf 109 Z-1 was introduced as a premium aircraft in Update 1.79 "Project X". The Z-1 is an incredibly fast aircraft with a top speed of over 700 km/h (435 mph) and is almost untouchable at high altitudes. Being a twin-engine fighter, dogfighting should not be performed, and players should opt to stick to boom and zoom tactics against enemy fighters. The four 30 mm MK 108 cannons have a high damage output, but they also lack velocity and range. It will be quite hard for players to engage at long range or aim in general due to the abysmal velocity. Players will have to lead a significant amount of rounds to hit on target.

The Bf 109 Z-1 was removed from the store after the War Thunder's 6th Anniversary sale. It was briefly made available during the 2018 Winter sale and the 2022 "Maiden flight of the Bf 109" event. It was also available after taking the new special quiz during the 2023 Christmas and New Year celebrations.