Question: The Boeing Boeing 737-300 traveling from Belize to New Orleans was operated by an airline that has been in operation for how long?

Context paragraphs:
Boeing 737 Classic: The Boeing 737 Classic refers to the -300/-400/-500 series of the Boeing 737.  It is the second generation derivative of the 737, following the original -100/-200 models that began production in 1966.  They are short- to medium-range, narrow-body jet airliners. Produced by Boeing Commercial Airplanes from 1984 to 2000, the 737 Classic includes three variants and can seat between 145 and 188 passengers.  Improvements over the previous generation of 737 aircraft included CFM International CFM56 high bypass ratio turbofan engines, upgraded avionics, and increased passenger capacity (in the -300/-400 models).

Avianca El Salvador: Avianca El Salvador, formerly Transportes Aereos del Continente Americano, simply known as TACA Airlines, is an airline owned by the Synergy Group based in El Salvador.  As TACA, it was the flag carrier of El Salvador.  As Avianca El Salvador, it is one of the seven nationally branded airlines (Avianca Ecuador, Avianca Honduras, etc.) in the Avianca Holdings group of Latin American airlines.  This Airline has been in operation for 75 years.

Keyway Air Transport: Keyway Air Transport was a United States airline that operated from Frankfurt International Airport (which at the time was also home to a United States Air Force facility; Rhein-Main Air Base) using a Boeing T-43 Bobcat (a military variant of the Boeing 737-200) and a Boeing 707-355C.  Details on its operation are unknown.  The 737-200 was operated by Keyway Air Transport from 1986 up until 1992, when it was transferred to defence contractor EG&G, who operated the aircraft in the Janet fleet up until 2009 when it was retired from service.  The Boeing 707-355C was operated from 1986 up until 1989, when it was transferred to HCL Aviation.  From 1992 onwards, after having been modified for military service by Raytheon, the aircraft was used by the United States Air Force as an airborne command post for the United States Central Command and later on was reported as being used by the Air Force Special Operations Command, before being put in storage at the 309th Aerospace Maintenance and Regeneration Group located on Davis–Monthan Air Force Base in 2002.

Wings of Lebanon: Wings of Lebanon is a privately held Lebanese airline, owned by the Nakhal group, which in July 2016 expanded its business model from pure charter operations to include largely seasonal scheduled international passenger services from its main base at Beirut Rafic Hariri International Airport.  The carrier has historically operated one Boeing 737-300, but has expanded its operations using a variety of wet-leased Boeing 737 aircraft as well as Airbus 319 and 321.

TACA Flight 110: TACA Flight 110 was an international scheduled airline flight operated by TACA Airlines, traveling from Belize to New Orleans.  On May 24, 1988, the Boeing 737-300 lost power in both engines, but its pilots made a successful deadstick landing on a grass levee, with no one aboard sustaining more than minor injuries.  The captain of the flight, Carlos Dardano of El Salvador, had lost one eye to crossfire on a short flight to El Salvador, which was undergoing a civil war at the time.

Panair: Panair was an airline based in Italy from 2001 to 2003.  It operated two aircraft, a Boeing 737-300 and a Boeing 737-400, the first of which was put in service with the airline in July 2001.  In March 2003, both were withdrawn, which marked the end of Panair's flight operations.

1983 TAME 737-200 crash: The 1983 TAME Boeing 737-200 crash was an aviation incident in which a Boeing 737-2V2 Advanced, operated by the Ecuadorian national airline TAME, which was flying on a domestic route from Mariscal Sucre International Airport in Quito to Mariscal Lamar Airport in Cuenca, crashed into a hill during final approach just one mile (1.6 km) from its final destination, killing all 119 people on board.

Boeing 737 Next Generation: The Boeing 737 Next Generation, commonly abbreviated as 737NG, is the name given to the −600/-700/-800/-900 series of the Boeing 737 airliner.  It is the third generation derivative of the 737, and follows the 737 Classic (−300/-400/-500) series, which began production in the 1980s.  They are short- to medium-range, narrow-body jet airliners. Produced since 1996 by Boeing Commercial Airplanes, the 737NG series includes four variants and can seat between 110 and 210 passengers.

Orion Airways: Orion Airways (known simply as 'Orion') was an airline based in the United Kingdom with its head office on the grounds of East Midlands Airport in Castle Donington, North West Leicestershire.  It was created as the charter airline of Horizon Travel and went on to successfully develop scheduled services.  The airline operated a fleet of Boeing 737-200s, Boeing 737-300s and Airbus A300s between 1979-1989.

Vision Air International: Vision Air International is a passenger and cargo charter airline based at Jinnah International Airport, Karachi, Pakistan.  Vision Air International registered as a Private Limited Company in June 2006 and in 2007 had already acquired its Air Charter License for Passenger and Cargo, Domestic and International operations.  Having initially operated Boeing 737-200 and -300 passenger aircraft Vision is now primarily focused on air cargo and operates Boeing 737 freighter aircraft.  Vision transports the majority of Pakistan’s air courier material on its nightly scheduled flights internally within Pakistan.

Supporting paragraphs: TACA Flight 110 Avianca El Salvador
Answer: 75 years