The Zerstörer doctrine assumed a heavy twin-engine fighter could dominate lighter aircraft through firepower, speed and range. Against the RAF in 1940 that assumption collapsed. The Bf 110 was fast in a straight line but heavy and slow to turn, and single-engine Spitfires and Hurricanes could out-manoeuvre it with ease. Escorting slow bomber formations forced the 110s to fly low and slow — exactly where their disadvantage was greatest.

Losses mounted so quickly that the Luftwaffe began assigning Bf 109s to protect the Bf 110s that were themselves supposed to be protecting the bombers. Crews adopted the Abwehrkreis — a defensive circle in which each aircraft guarded the tail of the one ahead — a tactic of survival, not attack. By the autumn of 1940 the Zerstörer arm had been mauled, and the type was quietly withdrawn from daylight fighting over Britain. Its salvation would come in a role no one had planned for it: the night defence of the Reich.

Schräge Musik — German slang meaning “slanted” or “jazz” music — was a pair of roughly 20 mm cannon mounted in the fuselage angled to fire upward and slightly forward. A night fighter would slide into the dark blind spot beneath a heavy bomber, below its defensive guns and the crew’s field of view, match speed, and then fire up into the wings and fuel tanks — deliberately avoiding the bomb bay, whose detonation could destroy the attacker as well.

The attacks were often invisible to the target and to nearby crews. For months RAF losses were misattributed to flak, and Bomber Command was slow to understand what was killing its aircraft. Combined with airborne radar, Schräge Musik turned the Bf 110 into one of the most lethal defensive weapons of the war.

From late 1941 Bf 110 night fighters carried FuG 202 and later FuG 220 Lichtenstein airborne interception radar, whose forward-projecting dipole arrays earned the nickname “stag’s antlers.” Working with ground controllers who vectored the fighter into the bomber stream, the radar operator — the second or third crew member — used the set to close the final gap in darkness until the pilot could see the target’s exhaust.

The aerials cost speed: their drag cut a G-4’s top speed by tens of km/h compared with a clean machine. For the Nachtjagd it was a trade well worth making. Radar plus Schräge Musik meant the Bf 110 no longer had to out-fly anyone — it simply had to find its prey and slip beneath it.

The Bf 110 was a product of the wartime German state economy, built to state contracts and never sold on an open market, so a firm flyaway unit price in modern terms does not exist in the public record. Contemporary figures were quoted in Reichsmark and are hard to convert meaningfully across eight decades of inflation, currency change and a command economy. No credible cost-per-flight-hour number exists for the type either. Any precise dollar figure attached to a Bf 110 today should be treated as an estimate, not a sourced fact.