Boeing 737-300

Updated: October 2026 – Two fat engines whose inlets look as if someone had squashed them flat at the bottom: anyone who stood at German airports in the 1990s and 2000s knows this sight. The Boeing 737-300 was the first version of the 737 Classic. With it, the 737 got the modern CFM56 engine, a longer fuselage and a second career that is not quite over yet. Here you read why the engines have such an odd shape, who flew the -300 in Germany, how it lives on as a freighter and how to reliably tell it from its siblings.

What is the Boeing 737-300?

The 737-300 is a twinjet narrowbody for short and medium routes with room for typically 126 passengers in two classes and up to about 149 in a dense layout. It is powered by two CFM56-3 engines from CFM International, a joint venture of GE and Safran. The range is about 4,200 kilometers – enough for European routes from Hamburg to the Canary Islands with reserves.

Together with the longer 737-400 and the shorter 737-500, it forms the 737 Classic generation. Before it came the 737-100 and 737-200 with slim JT8D engines, and after it the Next Generation and the MAX. You get the big overview of all generations in the article How to tell the Boeing 737 Original, Classic, NG and MAX apart, and more about the manufacturer on the Boeing page.

The backstory: why Boeing reinvented the 737

By the end of the 1970s, the 737-200 was a success, but its powerplant was getting old. The JT8D engines were loud and thirsty, and with stricter noise rules and high kerosene prices that became a problem. At the same time, airlines wanted more seats per flight. So in 1979, Boeing began developing a modernized 737, later known as the Classic.

The core of the plan was a new engine: the CFM56, a high-bypass turbofan, much more economical and quieter than the JT8D. The problem was its size. The 737 traditionally sits very low, so that passengers and baggage can get on board without much equipment. Under the wing there was simply no room for such a large fan.

Boeing solved this with several compromises at once. The engines moved onto pylons ahead of the wing leading edge and upward, the fan diameter was reduced somewhat compared with the base model of the CFM56, and the accessory gearbox moved from the bottom to the side of the nacelle. You can still see the result today: an inlet with a flattened underside, which spotters affectionately call the “hamster cheek.” The article How to recognize engines explains more details like this.

The rest of the aircraft was reworked too. The fuselage grew by about 2.9 meters, the wingtips were extended slightly, slats and flaps were adapted, and the vertical stabilizer got a dorsal fin where it meets the fuselage. Inside, Boeing modernized the cabin and systems without giving up the close kinship with the proven 737 – an important selling point for airlines with existing -200 fleets.

First flight, certification and success

The green light came in March 1981: USAir and Southwest Airlines each ordered ten 737-300s with options on another 20. The prototype rolled out of the hangar in Renton on January 17, 1984 and made its first flight on February 24, 1984. The US aviation authority FAA granted certification on November 14, 1984, the first deliveries followed at the end of November, and in December 1984 the type entered scheduled service with Southwest.

After that, things moved fast. In 1985 alone, Boeing collected 252 orders, and the peak delivery year was 1988 with 141 aircraft. When the last 737-300 went to Air New Zealand on December 17, 1999, 1,113 aircraft had been built. That made the -300 the most-built version of the Classic generation.

Southwest Airlines remained the most important operator: the Texans operated 195 in total and flew the -300 until September 29, 2017. On that day, flight WN68 from Houston Hobby to Dallas Love Field ended the Classic era at Southwest – shortly before the 737 MAX 8 entered service. US Airways, as USAir a co-launcher of the program, also used the type for a long time.

The 737-300 in Germany: Lufthansa, Germania and dba

For German spotters, the -300 is a piece of home. Three airlines in particular defined it here.

Lufthansa had already been launch customer of the original 737 and stayed true to the type. From the mid-1980s, the first 737-300s joined the fleet; the aircraft carried the customer code 737-330 and, as is usual at Lufthansa, city names. Among the crews, the 737 was fondly called “Bobby.” A -300 wrote a special chapter on August 10, 1989, when it operated the first scheduled flight between East and West Germany, from Frankfurt to Leipzig. For almost three decades, the type shaped the European network of Lufthansa, until the A320 family replaced it. The last scheduled flight landed in Frankfurt from Nuremberg on October 29, 2016, and on October 31, D-ABEC flew a farewell flight to Hamburg, home of Lufthansa Technik. Across all generations, Lufthansa operated 148 Boeing 737s in total. You can read more about the airline’s role in today’s group at the Lufthansa Group.

Germania used the -300 from 1987 and flew mainly vacation and charter traffic with it. In 1995, the Berlin-based company ordered twelve Next Generation jets as successors, and the first 737-700 arrived in 1998. Even so, the -300 did not disappear for a long time: in summer 2011, five were still in the fleet, one of them flying for the brand’s 25th anniversary as a “Signature Jet” with employees’ signatures on the tail. From 2011, Germania added Airbus A319s, and in 2012 the last -300 left the fleet. In 2019, the airline filed for insolvency.

Deutsche BA, later dba, put its first 737-300s into service in 1992 and flew only this type from 1998. Until the end of its independent flight operations in 2008, the 737 was a fixture at German domestic airports.

Airline	737-300 service	Note
Lufthansa	Mid-1980s to October 2016	Customer code 737-330, city names
Germania	1987 to 2012	Successor 737-700, also Airbus A319 from 2011
Deutsche BA / dba	From 1992, single-type fleet from 1998	Operations ended 2008

In the United Kingdom, Jet2 was long one of the largest European operators of the -300. You can find more chapters of German airline history in the look back at Air Berlin.

A second life as a freighter

When the big airlines gave up their -300s from the 2000s on, many airframes were far from the end of their lives. Their size suits express and mail traffic on short and medium routes well, so a conversion paid off. Several companies offer certifications for this.

AEI (Aeronautical Engineers Inc.) builds the 737-300SF: a hydraulically operated cargo door of about 2.2 × 3.6 meters on the left side of the fuselage, a main deck as a cargo compartment and, according to the manufacturer, room for ten pallets or containers on the main deck at up to about 19.5 tonnes of payload, depending on the base model. Pemco has also converted numerous -300s, including more than a dozen Classic aircraft for the Chinese cargo airline SF Airlines, where the -300 has nine pallet positions. The sister -400 is available as a freighter in a similar way; more on both conversions on the page 737-300SF and 737-400SF.

An unusual offshoot: Coulson converted six former Southwest aircraft into the 737 FireLiner, a firefighting aircraft that also keeps seats for emergency crews.

Today the -300 as a freighter is mostly out and about with smaller operators and on regional networks. For the next generation, Boeing has a larger conversion version in its program with the 737-800BCF, which is gradually replacing many Classic freighters. How to identify freighters in general is covered in the article How to recognize cargo aircraft.

How to recognize a 737-300

In the field, three steps are usually enough to place a -300 reliably.

How to check such features systematically is explained in the introduction Recognizing aircraft types for beginners.

Common mix-ups and how to rule them out

The most dangerous mix-up is with the 737-700: both fuselages are almost the same length, and the NG also has flattened engine inlets. The difference is in the wing. The -700 has a wingspan of over 34 meters, a wider wing chord and often carries winglets. The -300 looks short-winged next to it. Even the retrofitted blended winglets on some -300s do not help on their own; then you look at wing shape and tail. More about wingtips is in the article How to recognize winglets, sharklets and more.

Where to see the 737-300 today

In passenger service, the -300 has practically disappeared in Europe. Your best chances today are at cargo airports and in night traffic. In Europe, it is worth a look at hubs like Liège or Leipzig/Halle, where smaller cargo operators with older narrowbody jets show up. Whether a -300 is among them depends on the schedule – a tracker or an alert for the type saves you a lot of waiting. You can find tips for hunting rarities in Spotting rare aircraft.

If you want to see one without relying on luck, plan a museum visit. The very first Southwest aircraft, N300SW, is at the Frontiers of Flight Museum in Dallas, and another -300 is at the Pima Air & Space Museum in Tucson. Check before the trip whether the aircraft are currently accessible.

Photo tips for the 737-300

Which focal length is good for what is explained in Lenses and focal length for plane spotting.

Conclusion

The 737-300 brought the 737 into the modern age. With the CFM56, the classic became quieter and more economical, and the flattened engine inlets became the trademark of an entire generation. In Germany, Lufthansa, Germania and dba defined the type for decades before Airbus and the Next Generation took over. Today the -300 lives on mostly as a freighter, which makes it a rarity for spotters that you can hunt down deliberately.