United Airlines has emerged as a prominent operator of the Boeing 737 fleet, which includes both the 737NG (Next Generation) and 737 MAX series. Currently, United’s fleet consists of nearly 210 737 MAX aircraft and approximately 330 737NGs of various models, placing it as the third-largest 737 operator globally, following Southwest Airlines and Ryanair.
The Boeing 737, a narrowbody aircraft, announced its first delivery on February 10, 1968, with Lufthansa as its launch customer. United’s significant 737NG fleet originated mainly from its merger with Continental Airlines in 2010. Prior to the merger, Continental had placed its first 737NG order in 1996, eventually receiving over 200 airframes. During the two airlines’ discussions in 2008, Continental was the fifth largest U.S. carrier, operating over 300 aircraft, and had firm decisions made for future additions of aircraft.
In the merger with United, Continental handed over 350 aircraft, including 240 Boeing 737s with a significant portion being 737NG models. Continental’s fleet addition also comprised Boeing 767s and 777s. As part of the merger arrangement, United took control of Continental’s upcoming Boeing 787 Dreamliner order, planned for service commencement in the subsequent year.
Even after the merger, United maintained Continental’s aircraft commitments, including deliveries and options. The airline decided in 2012 to alter options for 737-700s to 737-900ERs to align with its route expansion plans. United later put in 100 firm commitments for the new 737 MAX series at the Farnborough Airshow the same year, alongside a 50-unit order for the 737-900ER.
The existing 737NG fleet at United varies in age, with some airframes being as old as 27 years. Notably, the 737-900ERs are newer, with ages ranging from 17 years to newer under 10 years. As part of modernizing its fleet, United operates both the MAX 8 and MAX 9 models and is waiting for the certification of the MAX 10, for which it is the launch customer. This transition includes retiring 20 older planes.
Worldwide, the Boeing 737NG fleet remains extensive, outnumbering the newer 737 MAX series. A strong order record underscores the 737NG’s industry impact, with the 737-800 being its most popular model. Despite its past difficulties, the 737 MAX series continues to gain traction among airlines, including United, reflecting confidence in its performance capabilities and awaited certification of newer variants.
Boeing’s 737 program, having sold nearly 7,000 NGs and thousands of MAX units, is recognized as a major milestone in aviation history. Although Airbus challenges this legacy with its A320 family orders, the Boeing 737 still boasts a larger number of deliveries.
