Boeing 747s on retirement mode
Several airlines are retiring their 747 fleet. In Picture: British Airways Boeing 747-400 takes off from London Heathrow Airport, England.Wiki Commons/Adrian Pingstone

One of the most iconic US aircraft, the Boeing 747, dubbed a symbol of American ingenuity, is facing retirement. Boeing has announced that it may not produce any more of these jumbo jets, 45 years after it was first deployed in service.

The huge commercial jet is finding few buyers now, since it guzzles more fuel. Also, with improvement in engine technology, two engines are considered more economical than the four engines found in the 747.

Who is retiring it?
Two of the biggest commercial airliners in US -- United and Delta -- have said they will be retiring their 747 fleet. United announced on November 17 that it would retire all 20 of the 747s in its fleet by October 2018. Delta too has said that it would be retire 747 by the end of 2017. Cathay Pacific has also given similar indications. 

Started as a military project, the 747 was promoted by Juan Trippe, the then president of Pan American World Airways (Pan Am).

The development of the aircraft was a technical and financial challenge and those on the project were billed "The Incredibles." Boeing had to build an assembly plant for the giant airliner.

The first aircraft was rolled out in September 1968, with the first flight of the new aircraft taking place in February 1969.

Boeing 747s on retirement mode
Boeing rolled out its first 747 aircraft in September 1968. In Picture: The Boeing 747, being displayed to the public for the first time.Wiki Commons/SAS Scandinavian Airlines

The first 747 entered service with Pan Am airline on its New York-London route in January 1970.

Boeing 747s on retirement mode
Pan Am was the first airline to buy 747s. In Picture: A Boeing 747 of Pan Am at Zurich Airport.Wiki Commons/Eduard Marmet

Why iconic
The Boeing 747 is one of the most recognisable jumbo jets that revolutionised long-distance air travel around the world and featured "wide-body." It was one of the fastest airliners in the world, reaching Mach.92.

One of iconic images has been the modified 747, carrying NASA space shuttle piggyback style. The aircraft could seat over 300 passengers and featured four prominent engines.

The US president's Air Force One uses a modified version of the commercial 747-8.

What would be flown instead of the 747s?
United airlines would be flying the newer Boeing 787 Dreamliner and Boeing 777 models. Delta would be using the new Airbus A330s that have been delivered to it and also the new Airbus A350s.

Now only a few airlines are ordering the 747s. Marketplace quoted Scott Hamilton, an aviation consultant, as saying that Lufthansa and Korean airlines are among those who are still ordering it. The order is about 30 or 40 planes between them.

Apart from the above airlines, UPS, world's largest package delivery company, has ordered 14 Boeing 747-8 cargo freighters and took an option for another 14.

Hence, it may still be some years before the Boeing shuts down its 747-8 production line.