What were the goals of strategic bombing in germany and the invasion of sicily?

The Allies were focused on cutting Germany's oil supplies and air plane factories. By destroying the aircraft, the Nazis would be crippled. They wouldn't be able to strike from the air. By also targeting the oil refineries, it would cripple the movement of troops and supplies. Tanks, jeeps, trucks couldn't run without it. Even the aircraft that did survive wouldn't be able to function.