2. He underestimated the strength of the British air force. The Royal Air Force (RAF) was smaller than the German Luftwaffe, but it was much better equipped. The British had developed new radar technology that allowed them to detect German planes approaching from a distance. They also had a new generation of fighter planes, like the Supermarine Spitfire, that were superior to the German planes.
3. He overestimated the effectiveness of his dive-bombing tactics. The Germans used dive-bombing tactics, in which bombers would come down from a high altitude and release their bombs just before they reached their target. This tactic was effective against ground targets, but it was not as effective against ships and aircraft. The British ships and planes were able to maneuver quickly and avoid the bombs.
4. He was surprised by the resilience of the British people. The British people endured months of bombing without losing their spirit. They continued to work, fight, and produce war materiel. Their resilience surprised Hitler and made him realize that he had underestimated them.
In conclusion, Hitler underestimated the British people in the Battle of Britain because he believed they would be quick to surrender, underestimated the strength of the British air force, overestimated the effectiveness of his dive-bombing tactics, and was surprised by the resilience of the British people.