As plans for invading Britain moved forward, Hitler issued Directive No. 17, ordering the Luftwaffe to destroy the Royal Air Force as quickly as possible. The directive prioritized RAF flying units, airfields, supply systems, and aircraft production, including factories making antiaircraft equipment. Hitler also kept for himself the decision on any terror bombing, holding back from attacks on central London not out of restraint but because he still hoped Churchill might make peace and wanted to avoid British retaliation against Berlin.

The directive marked a major strategic shift. The Luftwaffe itself later viewed it as a new kind of war: an air force trying, largely on its own, to crush an enemy’s fighting power through mass bombing until that enemy sought peace. Success against the RAF therefore became the immediate prerequisite for any German invasion.

Responsibility for the campaign fell to Hermann Göring, who named the opening Adlertag, or Eagle Day. After first setting the attack for August 5 and then delaying it to August 10, Göring met his senior commanders at Carinhall on August 6 to finalize the plan. He approached the operation with complete confidence that the Luftwaffe could deliver the decisive blow Hitler wanted.

Until this point, German air operations against Britain had been limited and probing, with smaller raids meant to test defenses and draw RAF fighters into battle. Now Göring envisioned a massive offensive. Encouraged by intelligence chief Beppo Schmid’s claims that the RAF had already been badly weakened and could not replace its losses, Göring and his commanders concluded that only four days would be needed to destroy Britain’s remaining fighter and bomber force before expanding attacks to airfields and aircraft factories across the country.

Göring then shifted hundreds of bombers to bases on the French Channel coast and in Norway and prepared an opening strike of about fifteen hundred aircraft, banking on speed and surprise. Yet this confidence rested on faulty assumptions. German pilots were not seeing a collapsing RAF in combat, and ace Adolf Galland later said Göring ignored fighter commanders who warned that Schmid’s estimates were unrealistic. With Eagle Day imminent, Germany was poised to launch its great assault on the RAF, but its plan was already compromised by overconfidence, bad intelligence, and dependence on the weather.