For more than 30 years it would be known as "the blackest day in aviation history." On September 6, 1970, members of the militant Palestinian group, the Popular Front for the Liberation of Palestine (P.F.L.P.), hijacked four commercial airplanes. They commandeered a fifth aircraft three days later. Wanting to attract attention to the Palestinian cause and secure the release of several of their comrades, the P.F.L.P. spectacularly blew up four of the planes.

Today the commanders who planned and carried out the attack resist comparison to the terrorists who masterminded the events of September 11, 2001: members of the P.F.L.P. were not religious extremists, but secular Marxist Leninists. And of the almost 600 passengers taken hostage, none were killed. And yet more than three decades later, it is clear that a connection exists between the two seminal events, that September 6, 1970 gave birth to a new era of terrorism.

In telling this dramatic and complicated story, award-winning producer Ilan Ziv interviews leaders of the P.F.L.P., militants who carried out the attack, journalists who covered the hijackings, crew members and passengers. More than just recounting the events of those tense September days, this American Experience production examines how and when Middle East militants began to see civilians as legitimate pawns in their struggles for self-determination.