Boeing 737-600 vs. McDonnell Douglas MD-11

Launched in 1998, the Boeing 737-600 is the smallest aircraft in the 737 Next Generation (NG) series. It succeeded the 737-500, and was a significant evolution in Boeing's narrow-body offerings. It featured many upgraded features from the previous 737s, including aerodynamics, engines, and avionics. As the smallest NG variant, the 737-600 was designed for efficiency and adaptability, catering to airlines requiring a compact jet for short to medium-haul routes.

This aircraft extends 102.4 feet (31.2 meters) in length with a wingspan of 112.6 feet (34.3 meters). The 737-600, with a typical seating capacity for 123 passengers, offers an ideal balance between passenger comfort and efficiency, making it a fitting choice for airlines serving routes with moderate passenger demand. Equipped with two CFM International CFM56-7B20 engines, the 737-600 has a total thrust of 45,400 lbf (202.0 kN). This engine power, coupled with a fuel capacity of 6,868 US gallons (26,000 liters), gives the -600 a range of 3,051 nautical miles (5,650 kilometers). The 737-600 has a cruise speed of 528 mph (850 km/h) enabling airlines to maintain efficient and swift operations, particularly beneficial for regional network connections.

In the late 1990s and early 2000s, the Boeing 737-600 competed with aircraft such as the Airbus A318 and Bombardier CRJ series, offering airlines a modern alternative in the narrow-body market. Airlines including Scandinavian Airlines (SAS), Westjet, and Air Algerie operated the Boeing 737-600. Ultimately, the -600 variant was not a popular model of the 737 due to its economics. The -700, only slightly heavier, had a much greater payload. Additionally, the larger market was moving more towards higher capacity narrow-bodies with lower unit costs and greater revenue opportunities.

The McDonnell Douglas MD-11 is a wide-body, tri-jet airliner, recognized for its extended range and enhanced capabilities in long-haul commercial aviation. As a successor to the iconic DC-10, the MD-11 incorporated advanced technology and design improvements, making it a significant model in the evolution of wide-body aircraft. The MD-11 took its maiden flight in 1990, and was produced until the turn of the 21st century. There are no MD-11s servicing passenger flights today, but some MD-11 are still being used for freight operations with FedEx, UPS, and Western Global Airlines.

With a length of 61.6 meters (202.1 feet), the MD-11 is notably longer than the DC-10, which provided increased passenger and cargo capacity. This extension in length was complemented by a wingspan of 52.0 meters (170.5 feet), which included winglets for improved aerodynamic efficiency. The MD-11's was equipped with GE CF6-80C2s or PW4000 turbofan engines, which delivered a total maximum thrust of 822.0 kN (123,000 lbf). With a substantial fuel capacity of 146,173 liters (38,615 US gallons), the MD-11 boasts a range of approximately 12,455 kilometers (6,725 nautical miles), enabling it to operate on intercontinental routes with ease.

The MD-11 comfortably accommodated 298 passengers, and could be designed to fit over 340 in a higher density configuration. The most common configurations for the twin aisle jet included 9 seats to a row (3-3-3 or 3-4-2).

In the competitive landscape of long-haul airliners, the McDonnell Douglas MD-11 was positioned as an alternative to models like the Boeing 747 and the Lockheed L-1011 TriStar. By 2004, most carriers that utilized the MD-11 for long-haul passenger routes had replaced it with the Airbus A330, A340, and Boeing 777. When Boeing acquired McDonnell Douglas in 1997, it ultimately created internal competition for the MD-11 with the 767 and 777. A lack of interest from the market also lead to Boeing cutting production for the commercial variant short, while the freight version was continued for slightly longer.

KLM, Swissair, and Delta Air Lines were among the airlines who utilized the aircraft's range and capacity to expand their international route offerings. The MD-11's operational role was characterized by its ability to efficiently serve long-haul routes, offering a blend of passenger comfort and operational economics. Some airlines like China Eastern Airlines and Korean Air had converted their MD-11 aircraft into freighters rather than selling or retiring them.

The MD-11's production and service history reflect its role as a pivotal model in the wide-body aircraft segment. Its design and technological advancements, including the use of winglets and a glass cockpit, marked important steps in the advancement of commercial aircraft design. Although its production was eventually surpassed by more modern aircraft, the MD-11 remains a notable aircraft in the history of aviation, particularly for its contributions to long-haul air travel.