Gemini 200 1:200 Boeing 737-800: American Airlines, Reno Air Retro Livery

The Boeing 737 is a narrow-body aircraft produced by Boeing Commercial Airplanes at its Renton Factory in Washington. Developed to supplement the 727 on short and thin routes, the twinjet retains the 707 fuselage cross-section and nose with two underwing turbofans. Envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered service in February 1968 with Lufthansa. The lengthened 737-200 entered service in April 1968. It evolved through four generations, offering several variants for 85 to 215 passengers.

The -100/200 original variants were powered by Pratt & Whitney JT8D low-bypass engines and offered seating for 85 to 130 passengers. Launched in 1980 and introduced in 1984, the 737 Classic -300/400/500 variants were re-engined with CFM56-3 turbofans and offered 110 to 168 seats. Introduced in 1997, the 737 Next Generation (NG) -600/700/800/900 variants have updated CFM56-7s, a larger wing and an upgraded glass cockpit, and seat 108 to 215 passengers. The latest generation, the 737 MAX -7/8/9/10, powered by improved CFM LEAP high bypass turbofans and accommodating 138 to 204 people, entered service in 2017. Boeing Business Jet versions are produced since the 737NG, as well as military models.

As of December 2019, 15,156 Boeing 737s have been ordered and 10,571 delivered. Actual backlog stands at 4,398 when including "additional criteria for recognizing contracted backlog with customers beyond the existence of a firm contract". It was the highest-selling commercial jetliner until being surpassed in total orders by the competing Airbus A320 family in October 2019. Before, it competed primarily with the McDonnell Douglas DC-9, then its MD-80/MD-90 derivatives. In March 2019, the Boeing 737 MAX was grounded worldwide following two fatal crashes.

The Boeing 737 Next Generation, often called the 737NG, is a family of Boeing 737s. The 737-600, -700, -800 and -900 are all 737NG aircraft. It is the third family of Boeing 737. The family which came before it is the 737 Classic (−300/-400/-500) family. They have been made since 1996 by Boeing Commercial Airplanes. All 737s are twin-engined, narrow-body airliners. This means that they all have two engines and only have one aisle between seats.

4,293 737NG aircraft have been delivered (as of December 2012). More than 6,300 have been ordered by airlines. Southwest Airlines has more 737NGs than any other airline. Ryanair, a low-cost airline from Ireland, also has a lot of 737NGs. The only planes Ryanair has are 737-800s. The main rival of the 737NG family is the Airbus A320 family. The Boeing 737 MAX will eventually replace the 737NG.

After Airbus launched the Airbus A320, Boeing started designing a new series of Boeing 737. The 737 Next Generation (NG) program was announced on November 17, 1993. Boeing made many changes from the 737 Classic. The wing was changed. These changes made its area bigger by 25%. The wingspan was made bigger by 16 ft (4.88 m). These changes meant that it could carry 30% more fuel. CFM56-7B engines were used. These improvements allowed the 737 to fly 900 nmi farther.

The inside of the 737 Next Generation was better than the style used on the Boeing 757-200 and the Boeing 737 Classic. It used certain parts of the Boeing 777's inside style. The style of the 737 Next Generation was made the usual style of the Boeing 757-300.

In 2010, the inside of the 737NG was changed to look like the Boeing 787 Dreamliner. The new design was called the Boeing Sky Interior. The Sky Interior can only be put into new aircraft. However, a different company has made a style for 737 and 757 aircraft which looks like the Sky Interior.

The 737-800 is a longer version of the 737-700. It replaces the 737-400. For many airlines in the United States, the 737-800 replaced Boeing 727-200s.

The 737-800 is one of the planes which replaces the McDonnell Douglas MD-80. It burns 850 US gallons (3,200 L) of fuel every hour. That is about 80% less fuel than an MD-80.

The 737-800's main rival is the Airbus A320.

Reno Air was a scheduled passenger airline headquartered in Reno, Nevada, United States. Reno Air provided service from its hubs at Reno/Tahoe International Airport in Reno, Nevada, San Jose International Airport in San Jose, California and Las Vegas International Airport in Las Vegas, Nevada to destinations throughout the western United States, including Alaska. International service to Vancouver, British Columbia in western Canada was also served at one point and limited service was operated to the midwestern U.S. as well. A small stand alone operation was also undertaken at one point in the southeastern U.S. with the service being based in Gulfport, Mississippi. 

In February 1999, Reno Air was purchased by American Airlines, and flew its last flight on August 30 of that year. At the time, the purchase was seen as a way to feed American's east-west route network with Reno Air's north-south flights, primarily through San Jose. American initially retained the former Reno Air aircraft and repainted them into a modified version of the American Airlines color scheme (with a white fuselage instead of an unpainted one), but disposed of the entire Reno Air fleet in 2001 as part of capacity reduction efforts following the 9/11 attacks. By the end of 2001 (especially after 9/11) the original Reno Air route system structure had ceased to exist with American Airlines downgrading Reno to a spoke city rather than a connecting hub.

In 2015 American Airlines added to its heritage livery series a Reno Air Boeing 737-800 (although Reno Air never operated 737 aircraft).