List of Aircraft Hijackings: 1970s
Marxists* January 1, 1970: a Cruzeiro do Sul Sud Aviation SE-210 Caravelle VI R en route from Montevideo to Rio de Janeiro, with 33 occupants aboard, was hijacked by 6 persons who demanded to be flown to Cuba. The flight was diverted to Lima, Panama City and arrived in Havana two days later. There were no victims.
American/Suicidal?* United States March 17, 1970: Eastern Air Lines Shuttle Flight 1320, carrying passengers from Newark to Boston was hijacked around 7:30 P.M. by John J. Divivo who was armed with a .38 caliber revolver. Captain Robert Wilbur Jr., 35, a former Air Force pilot who had only been promoted to captain six months prior, was shot in his arm by the suicidal hijacker.
Marxists* March 31, 1970: Japan Airlines Flight 351, carrying 131 passengers and 7 crew from Tokyo to Fukuoka, is hijacked by nine members of the Japanese Red Army group.
Marxists* July 1, 1970: a Cruzeiro do Sul Sud Aviation SE-210 Caravelle VI R registration PP-PDX en route from Rio de Janeiro to São Paulo with 31 occupants was hijacked by 4 persons who demanded the release of political prisoners that were to be taken to Cuba.
Marxists* September 1970: As part of the Dawson's Field hijackings, PFLP members attempted to hijack four aircraft simultaneously. They succeeded on three and forced the planes to fly to the Jordanian desert, where the hijackers blew up the aircraft after releasing most of the hostages.
Lithuanians? Now apparently Americans, interesting.* October 15, 1970: Aeroflot Flight 244 was hijacked from Batumi, Adjar ASSR, Georgian SSR, to Trabzon, Turkey by a Lithuanian national and his son. An air hostess was killed and some other crew were injured in a shootout. The hijackers later received American citizenship.
Kashmiri Seperatists* January 30, 1971: Indian Airlines Fokker F27 on scheduled Srinagar-Jammu flight is hijacked to Lahore by two self-proclaimed Kashmir Separatists. All passengers were released by February 2 and repatriated to India, but the aircraft was blown-up—leading to an India-Pakistan air-travel ban, and suspension of overflight rights until 1976.
Anti-Government Filipinos* March, 1971: Philippine Airlines flight was hijacked in March 1971 by six students from the Mindanao State University, opposed to the Marcos government. The plane landed in Guangzhou (Canton) in southern China, and the Chinese authorities let the students stay in the country. The plane was then allowed to fly back to the Philippines. No one was hurt.
No information, but ended up in West Germany* May 1971: an IL-14 with 4 staff members and 16 passengers was hijacked by 6 men at the Oradea Airport (Romania), then forced to flew to Budapest (Hungary), then Vienna (Austria). The passengers and the crew were released in Vienna, while the hijackers flew to West Germany.
Amercan/Ransom* November 24, 1971: A man who became known as D. B. Cooper hijacked Northwest Orient Airlines Flight 305, a Boeing 727-100 aircraft flying from Portland, OR, to Seattle, WA, received US$200,000 in ransom, and parachuted from the plane. The actual name of the hijacker remains unknown.
American/Ransom* January 12, 1972: Braniff Flight 38, a Boeing 727, was hijacked as it departed Houston, Texas bound for Dallas, Texas. The lone armed hijacker, Billy Gene Hurst, Jr., allowed all 94 passengers to deplane after landing at Dallas Love Field but continued to hold the 7 crewmembers hostage, demanding to fly to South America and asking for US $2 million, parachutes, and jungle survival gear, amongst other items.
American/Ransom* January 28, 1972: TWA Flight 2, Los Angeles to New York, was hijacked by con man and bank robber Garrett Trapnell while over Chicago. Trapnell demanded $306,800 in cash (to recoup the loss of a recent court case), the release of Angela Davis (as well as that of a friend of his who was also imprisoned), and clemency from President Richard Nixon.
American/Ransom?* November 10, 1972: Southern Airways Flight 49, was hijacked by three men and flown to multiple locations in the United States, and one Canadian city. At one point, the hijackers threatened to fly the plane into the nuclear reactor at the Oak Ridge National Laboratory, if their demands for $10 million in cash were not met.
Croatian/Fascists* April 24, 1973: SAS DC 9 - Gunder Viking - with registration number LN-RLO on route from Torslanda, Gothenburg, Sweden, to Stockholm, Sweden, was hijacked five minutes after take off by 3 armed Croatian terrorists connected to Ustasja.
Already half way through, and I don't see any Islamist terrorists. Perhaps the Kashmiri separatists might have had some Islamist links, but it's not mentioned.
Seems that Marxists, greedy Americans, and variouos other nutjobs from around the globe were the founders of what you classify as terrorism.