It was the plane that many at Boeing didn't want to build and it has just turned 10,000 - that is 10,000 built to set a new world record. Thousands of Boeing employees have gathered at the company's Renton, Wash. factory today to celebrate the 10,000th 737 to come off the production line. With the 737 MAX 8 for Southwest Airlines, the 737 has broken the Guinness World Records title for the most produced commercial jet aircraft model. "This incredible milestone is a testament to the work we do every day to build the most reliable and efficient single-aisle airplane in the world," said Boeing Commercial Airplanes president and CEO Kevin McAllister. "It represents more than 50 years of success and achievement on the part of thousands of Boeing employees past and present, our supplier partners, and our airline customers around the globe who put their confidence in the 737."

Boeing will increase 737 production from the current rate of 47 airplanes per month to 52 airplanes per month later this year as Boeing has a backlog to build of more than 4,600 airplanes fueled by sales of the newest version of the 737, the 737 MAX. A 737 takes off or lands every 1.5 seconds and on average, more than 2,800 737s are in the air at any given time. All told than 22 billion people have flown on a 737 and it has flown more than 122 billion miles, the equivalent of 5 million times around Earth. SEE: Spectacular images and video of Qantas' 787 Quokka. Many at Boeing never wanted to build the world’s bestselling and most reliable plane and at one stage the non-believers almost sold the design to a consortium of Japanese aerospace manufacturers. Key to the success of the 737 has been the ability of Boeing to improve the plane. The latest design, the MAX, is the fourth major upgrade. Boeing started studies of a short-haul jet plane to supplement the company's very successful 727 for short routes. Design work began in May 1964, with the original design for a 60-passenger plane for routes up to 1600km. Many in Boeing thought the move was crazy because three other competitors already had similar jets flying or about to fly and there were few major customers left. But Boeing had a major advantage with its family concept as its 737 would use many of the parts and the same cabin cross-section (six across) as its best-selling 707 and 727. Boeing’s sales pitch was a big-jet comfort on regional routes. Germany’s Lufthansa and United Airlines were sold and the 737 was launched.

By the time the first flight took place in April 1967, 17 airlines had signed up. However, storm clouds were brewing for Boeing. By 1969 the 747 was in trouble with its weight and engine performance and Boeing’s Super Sonic Transport had to be totally redesigned. In 1970, starved of funds, Boeing looked for products to quit and the 737 which had sold only 23 that year was the prime candidate. The 747’s issues were resolved with compromises on all sides, the US government canceled the SST in 1971 and the pressure came off. The future was not going to be high-speed travel across the globe but more a focus on regional flights connecting thousands of cities, with the 737 set to be both the magic carpet and a golden goose. There is possibly no better example of how engine and aerodynamic technology has advanced aviation than the 737. The first 737 could carry 124 passengers over 2775km, whereas the latest version to fly, two weeks just last Friday, the 737MAX 9 can carry 204 passengers in the same configuration over 7000km. And the fuel consumption improvements have been spectacular.

Since 2000, for instance, the fuel burn has declined 20 percent from the current model in airline service to the MAX. As well as countless under-the-skin improvements, Boeing has given the 737 a new interior incorporating design concepts from its bigger brothers the 787 and 777. Dubbed the Sky Interior, it totally transforms the 737.