The Boeing 737-400 is a stretched version of the 737-300, developed to accommodate more passengers while retaining the efficiency and performance improvements introduced with the “Classic” series. First flown in 1988, the 737-400 offered airlines a cost-effective solution for short-to-medium-haul routes with higher demand, making it a popular choice for high-density domestic and regional markets.

The 737-400 retained the CFM56 engines and updated systems of the -300 but added nearly 10 extra feet in fuselage length, allowing for a typical capacity increase of around 20 passengers. Though later overshadowed by newer 737 Next Generation (NG) models, the -400 served as a workhorse for airlines around the world well into the 2010s, and many have been converted into freighters.

Key Specifications (737-400)

• Crew: 2 (Pilots).
• Capacity: Typically 146–168 passengers.
• Length: 36.45 m (119 ft 7 in).
• Wingspan: 28.88 m (94 ft 9 in).
• Height: 11.13 m (36 ft 6 in).
• Max Takeoff Weight (MTOW): ~68,000 kg (150,000 lb).
• Engines: 2 × CFM International CFM56-3C turbofans.
• Cruise Speed: Mach 0.74 (~795 km/h or 493 mph).
• Range: ~3,700 km (2,300 mi).
• Ceiling: ~37,000 ft (11,300 m).

Notable Features

• Stretched fuselage compared to the 737-300, allowing increased passenger capacity.
• Same systems and cockpit layout as the rest of the 737 Classic family, easing pilot training and maintenance.
• Widely used on short-to-medium routes with moderate-to-high traffic demand.
• Available in combi and freighter versions (737-400C and 737-400F), many of which are still active.
• Proven durability, with many aircraft logging decades of active service.

Operators & Usage

• Operated by major airlines including Alaska Airlines, British Airways, US Airways, Piedmont Airlines, and Malaysia Airlines.
• Over 480 units built, making it the largest model in the 737 Classic family.
• Many aircraft later converted into freighters and continue flying for cargo airlines like ASL Airlines, DHL, and Kalitta Charters.
• Phased out of major airline service in favor of more efficient 737 NG and MAX models, but still active in secondary markets.