Winning the battle in the air was important for Germany during World War II because it would have allowed them to gain control of the skies over Britain and launch a ground invasion of the country. This would have been a major strategic victory for Germany, as it would have eliminated Britain as a major military power and given Germany a foothold in Western Europe.
In addition, control of the air would have allowed Germany to disrupt British supply lines and prevent the British from receiving military aid from the United States and other allies. It would have also enabled Germany to launch bombing raids on British cities, which would have weakened the morale of the British people and forced the country to surrender.
Overall, winning the battle in the air was a key objective for Germany during World War II, as it would have given them a significant advantage in the war and allowed them to achieve their strategic goals.