The war began by Egypt planning to capture Israel, which was seen by the Arab world as an illegitimate state. The war also began because of fear of an attack from Israel as suggested by soviet intelligence and from internal pressure within Egypt. Egypt, Syria, and Jordan gathered troops and prepared for battle, and Arab authorities made clear their intentions for the destruction of Israel. Israel began the mounting precautionary troops against their borders with Syria, Egypt and Jordan as their prime reason.
The Israeli air raids were described as preemptive, a first strike against the Egyptians. This surprise attack was against the Egyptian airfields. The Egyptians had 50 runways and about 960 attack aircraft, and the Israelis had 300 attack craft. Israel attacked while Egypt's planes were still on the ground. In three, hours nearly the entire Egyptian Air Force was wiped out. That surprised the Egyptians, and Israel went on to attack on the ground. Israel was then attacked by Syria and Jordan and defeated them both.
The entire war lasted only six days. As a result, Israel claimed lands that had great strategical and historical importance for it. The war led to the 1973 Yom Kippur War, where Egypt took back part of the Sinai, but Israel took part of the West Bank. Eventually, Israel returned the Sinai Peninsula to Egypt but kept the lands acquired from Jordan. The UN requested Israel to retreat to the pre-1967 borders and to help form an Arab-Palestinian state. Negotiations and intermittent fighting continued.
Egyptian President Gamal Abdel Nasser has been described as the first leader of an Arab nation who challenged what was perceived as the Western dominance of the Middle East. He ordered a concentration of Egyptian military forces in the sensitive Suez zone. That act was highly provocative, and the Israelis viewed it only one way: Egypt was preparing to attack.
The Palestine Liberation Organisation (PLO) was established in May 1964 in Jordan and combines various Arab organisations under one banner. In its infancy, the PLO was not associated with violence, but from 1967 on, it became dominated by an organisation called Fatah, meaning "liberation" in Arabic. It was the Syrian wing and was led by Yasser Arafat.
Before the war, Israeli pilots and ground crews had trained extensively in rapid refitting of aircraft returning from sorties to allow a single aircraft to sortie up to four times a day; the norm in Arab air forces was one or two sorties per day. That enabled the Israeli Air Force (IAF) to send several attack waves against Egyptian airfields on the first day of the war, overwhelm the Egyptian Air Force, and knock out other Arab air forces on the same day. The Arabs were so surprised that many have mistakenly believed that Israel had foreign help, especially from the United States.
On May 26, 1967, the Central Intelligence Agency estimated, "The Israelis ... If they attack now they ... would still be able to drive the Egyptians away from the entrance to the Strait of Tiran, but it would certainly cost them heavy losses of men and matériel.
On the eve of the war, Israel believed it could win a war in 3–4 days. The United States estimated that Israel would need 7–10 days to win. British estimates supported that view.
The Israeli Army had a total strength, including reservists, of 264,000, but that number could not be sustained, as the reservists were vital to civilian life. Israel deployed about 40,000 troops and 200 tanks (8 brigades). Israeli Central Command forces consisted of five brigades. The first two were permanently stationed near Jerusalem and were called the Jerusalem Brigade and the mechanized Harel Brigade. Mordechai Gur's 55th paratrooper brigade was summoned from the Sinai front. The 10th Armored Brigade was stationed north of the West Bank.On the eve of the war, Egypt massed approximately 100,000 of its 160,000 troops in the Sinai, including all of its seven divisions (four infantry, two armoured, and one mechanized), four independent infantry brigades, and four independent armoured brigades. No fewer than a third of them were veterans of Egypt's continuing intervention into the North Yemen Civil War and another third were reservists.
With the exception of Jordan, the Arabs relied principally on Soviet weaponry. Jordan had an army was equipped with American weaponry, and its air force was composed of British aircraft.
Egypt had by far the largest and the most modern of all the Arab air forces, consisting of about 420 combat aircraft, all of them Soviet-built and with many top-of-the line MiG-21s. Of particular concern to the Israelis were the 30 Tu-16 "Badger" medium bombers, which could inflict heavy damage on Israeli military and civilian centers.
- "The Six Days War". History Learning Site. HistoryLearningSite.co.uk. Retrieved 5 February 2015.