As Hitler proceeded with his invasion plans, code-named Operation Sealion, he knew that the RAF must not be allowed to threaten the invading forces as they crossed the Channel. It was clear that they would have to be brought to battle and defeated. Still hopeful of a settlement, Hitler believed that a sustained aerial attack, coupled with a U-Boat blockade, might bring Britain to the negotiating table. The Luftwaffe's specific aim was to win superiority by luring Fighter Command into the air and wiping it out. But Fighter Command, with its pilots, aircraft, and carefully considered systems of control, was waiting.