Adlertag, Eagle Day, August Thirteenth, Nineteen Forty, and the Morning Hermann Goering Promised to Wipe the RAF From the Sky in Four Days

Adlertag - “Eagle Day” - was the Luftwaffe’s grand opening attack of the Battle of Britain, launched on August 13, 1940. Hermann Goering promised it would destroy RAF Fighter Command and clear the skies over England in a matter of days. Instead, bad weather, a botched recall order, and a British early-warning network the Germans never understood turned the “knockout blow” into one of the costliest days of the campaign for the Luftwaffe.

What Was Adlertag (Eagle Day)?

By the summer of 1940, France had fallen and the British Army had been driven off the beaches at Dunkirk. Hitler wanted to invade England in an operation called Sea Lion, but no invasion fleet could cross the Channel while the RAF still controlled the air above it.

That job fell to Hermann Goering, head of the Luftwaffe. His plan for winning air superiority was named Adlerangriff (“Eagle Attack”), and its opening blow - the intended knockout punch - was Adlertag (“Eagle Day”), scheduled for August 13, 1940.

Goering was confident to the point of fantasy. A genuine fighter ace of the First World War with 22 victories and the last commander of the famous “Flying Circus” after the Red Baron’s death, by 1940 he was more showman than warrior - loud, vain, and certain his air force could do whatever he claimed over a map table. He told Hitler he could finish Fighter Command in days.

Who Was Hermann Goering and Why Did He Think He Could Win?

Goering’s plan looked flawless on paper. Wave after wave of bombers - Dornier 17s (the “flying pencils”), Junkers 87 Stukas with their screaming sirens, and Heinkel 111s - would strike the RAF’s airfields, escorted by swarms of Messerschmitt Bf 109 fighters flown by men who had already conquered a continent.

The real targets should have been the RAF’s fighter airfields and the coastal radar stations. Knock out the eyes and the runways, and Fighter Command would have no warning and nowhere to land.

There were two fatal problems.

Why Did Eagle Day Go Wrong?

The first problem was the weather. Eagle Day dawned socked in - low cloud on the treetops and poor visibility over the Channel, exactly the conditions in which bombers cannot find their targets, coordinate, or even see their escorts. Watching the forecast from his headquarters, Goering lost his nerve and ordered the attack postponed to the afternoon.

The recall order never reached everyone. A formation of Dornier 17 bombers from Kampfgeschwader 2 (KG 2) was already airborne and climbing over the coast. Their Bf 109 escorts got the message and turned for home - but the bombers did not. Barely eight o’clock in the morning, a full formation of unescorted bombers was droning across the Channel in bad weather with no fighter cover and no idea they had been left exposed.

What Was the Dowding System and Chain Home Radar?

The second problem was the one Goering never grasped: the British could see him coming.

Along England’s south coast stood a chain of tall lattice towers - a radar early-warning network the British called Chain Home. Crude by modern standards, it could bounce a radio pulse off an incoming formation and estimate its size, height, distance, and bearing. The Germans saw the towers, even hit a few, but never understood what they were connected to.

Behind the radar sat the real secret weapon: the Dowding System, named for Air Chief Marshal Hugh Dowding, the cold, meticulous commander of Fighter Command and one of the most underrated figures in aviation history. It worked like a nervous system:

A radar station spots a raid forming over France and phones in the plot.
A filter room sorts real raids from friendly flights and false echoes.
The plot goes onto a large table map, where Women’s Auxiliary Air Force operators push wooden blocks across a map of England with croupier rakes.
A calm controller reads that map and vectors exactly the right number of Spitfires and Hurricanes to the right place at the right altitude.

The winning edge was not a faster fighter or a bigger gun. It was information - the right information, in the right hands, in time to act. The Germans were flying blind and swinging hard; the British were flying with their eyes open and hitting precisely where it mattered.

What Happened on August 13, 1940?

The unescorted KG 2 Dorniers were bounced by Spitfires and Hurricanes that a controller had positioned before the raid even finished forming up. The bombers scattered, and the grand opening of Eagle Day fizzled in confusion.

When the weather lifted in the afternoon, Goering threw in the rest. The Luftwaffe flew roughly 1,500 sorties - an enormous effort - and dropped a great many bombs. But much of it was wasted: they repeatedly plastered airfields that did not belong to Fighter Command, including Bomber Command and Coastal Command bases whose loss cost Dowding not a single defending fighter. They were swinging a sledgehammer in the dark.

The Junkers 87 Stuka paid an especially heavy price. Fitted with wind-driven “Jericho trumpet” sirens, it had terrorized Poland and France - but a dive bomber pulling out low, slow, and heavy at the bottom of its dive is one of the easiest targets in the sky. The Hurricanes butchered them so badly that the Germans eventually withdrew the Stuka from the battle entirely.

Who Won Eagle Day?

The scoreboard tells the story. The Luftwaffe lost around 45 aircraft that day. The RAF lost roughly a dozen fighters - and, critically, most of those British pilots parachuted onto their own soil to fly again the next day. A German crew downed over Kent went into captivity or the ground; a British pilot who bailed out over the same fields was back in the mess by supper.

That asymmetry is the whole Battle of Britain in a single line: when you fight over your own front yard, every parachute is a save; when you fight over the enemy’s, every parachute is a loss.

German intelligence made it worse. Their chief intelligence officer had spent weeks assuring Goering that Fighter Command was nearly finished. Pilots kept claiming more RAF machines destroyed than the RAF even possessed - yet every morning the Spitfires and Hurricanes were still climbing to meet them, because British factories were replacing losses faster than the Luftwaffe could inflict them, and the Dowding System made each fighter count for three.

Why Adlertag Still Matters for Pilots Today

The Luftwaffe was a superb tactical air force built to support an army advancing over land. It had never been designed to fight a long, grinding strategic campaign across open water against an enemy who could see it coming. Over Kent, Sussex, and the Thames Estuary, that difference proved fatal.

The enduring lesson is that the airplane is never the whole story. The decisive advantage in August 1940 was not stamped out of aluminum - it was a system of towers, telephone lines, calm voices, and wooden blocks on a map, all delivering one thing worth more than another ten knots of speed: knowing what’s out there before it’s on top of you.

Every pilot flying today lives inside a descendant of that idea. Every traffic call from a controller, every diamond that lights up on a cockpit display, every in-flight weather picture is a direct heir to Chain Home and that filter room - proof that a pilot who knows is worth two who are guessing.

Key Takeaways

Adlertag (Eagle Day) was launched on August 13, 1940, as the opening blow of the Luftwaffe’s Adlerangriff offensive and the Battle of Britain.
Hermann Goering promised to destroy RAF Fighter Command within days but was undone by weather, a failed recall order, and flawed intelligence.
The Dowding System and Chain Home radar gave the RAF decisive early warning - an information advantage the Germans never understood.
The Luftwaffe lost about 45 aircraft to the RAF’s ~12 fighters, and most downed British pilots survived to fly again because they fought over home soil.
The lasting lesson is that situational awareness - not raw aircraft performance - wins in the air, the same principle behind modern traffic alerts, radar, and cockpit weather.

Sources: Records of the RAF, accounts held by the Imperial War Museum, and first-hand recollections of the pilots on both sides who lived it.