Likely answer: Israel's retaliation against its attackers.
Explanation: There was much tension in the region in the time leading up to the 1967 Six Day War. Israel had been involved in skirmishes with Syria to its north. Egypt was building up its military forces and expelled UN peacekeeping forces from the Sinai Peninsula, posing a threat to Israel. Israel decided to launch a preemptive strike against Egypt, and then expanded its air force attacks also against Syria, Jordan, and Iraq. Israel won the conflict quickly and convincingly. It's called the Six Day War because it took Israel only six days to accmplish its goals and gain control of much territory.