On September 6 1970, Haddad ordered the simultaneous hijacking of four airliners bound for New York. Leila Khaled, one of Haddad's trusted lieutenants, led the first attack. Khaled had come to notoriety when she had successfully hijacked a TWA flight to Damascus in 1969. In July 1970, Khaled had escaped serious injury when remote controlled rockets were fired into Haddad's house during a meeting. Incredibly, two of the four rockets failed to explode but Haddad's wife and eight-year-old son, who were in another room, received cuts and burns. Haddad blamed Mossad, Israel's secret service, for the attack.

Khaled's mission was to hijack an El Al flight, which was en-route to New York from Tel Aviv via Amsterdam. The plan was for Khaled and her accomplice, Patrick Arguello, to pose as a married couple and take control of the aircraft. As the plane approached the English coast, the pair rose from their seats and, brandishing guns, made their way to the cockpit. As they reached the flight deck the pilot thrust the aircraft into a steep nosedive throwing the terrorists off their feet. In the scuffle that followed, Arguello threw a hand grenade down the aisle of the plane and was shot dead shortly after by an El Al "sky marshal." Fortunately the grenade failed to explode. Khaled was overpowered by male passengers and savagely beaten as she tried to retrieve her own grenades, which had been secreted inside her brassiere.

After an emergency landing at Heathrow Airport, Khaled became the subject of a heated argument as El Al security and British police fought over who had jurisdiction over the prisoner. Eventually the Israelis conceded defeat and Khaled was taken into British custody.

Dawson's Field, 1970

The second attack also met with problems when the Pan Am 747 was found to be too big to land at the Jordanian airstrip that Haddad had selected. Instead it was flown to Cairo where the passengers and crew were ordered off before the plane was blown up. The other two aircraft, a Swissair DC8 from Zurich and a TWA 707 from Frankfurt were successfully captured and flown to Zarqa airstrip in Jordan as planned. In honour of the event the Palestinians renamed Dawson's Field, a former British airstrip, "Revolution Airstrip." In a public announcement, the Popular Front described the attacks as the first strike in avenging "the American plot to liquidate the Palestinian cause by supplying arms to Israel." They further ordered the Swiss and West German governments to release several of their jailed comrades.

A further hijacking by a Popular Front sympathizer saw a BOAC flight from Bombay to London carrying 150 passengers taken hostage and held at Zarqa pending Khaled's release. After twenty-four hours of intense negotiations, 360 passengers and crews were released in exchange for Khaled and six other convicted terrorists. As a final act of revenge, terrorist bombers destroyed the aircraft. Carlos, as a new recruit with no experience, was not used in the attacks but spent the time guarding a munitions depot far from the action.

Prior to the hijackings, King Hussein of Jordan had been mostly sympathetic to the Palestinian cause and had allowed over fifty terrorist groups into his country. Tensions had been mounting however, since Palestinian attacks on Jewish targets had increased Jordan's vulnerability to retaliatory strikes from Israel. The tension increased in February 1970 when Jordanian troops, attempting to enforce a royal decree that ordered the Palestinians to surrender their guns and explosives, clashed with the "freedom fighters" in a street brawl that lasted three days. The decree was later abandoned.

Incensed that the Popular Front would have the audacity the carry out such an act on Jordanian soil without his consent, Hussein decreed marshal law and raised his Bedu army to drive the Palestinians out of Jordan. The resulting conflict was dubbed "Black September" and was to become Carlos's first taste of real warfare.