The first few days of the 1973 Yom Kippur War saw major Arab ground breakthroughs, surprising Israel who, after its lopsided 1967 victory, considered its air supremacy sufficient to blunt or dissuade any conventional attack. Despite Egypt and Syria having rebuilt their air forces since 1967, Israel continued to deny them the airspace over the battle area; however, these Arab forces were able to control losses and shoot down Israeli air support aircraft by employing mobile surface to air weaponry which travelled along with invading units. Most of Israel's air power in the first few days was directed to reinforce the badly mismatched garrison overlooking the besieged Golan Heights which was under attack by Syria.