The creation of reliable, fuel-economical, and high-performing jet engines completely revolutionized flying in the 20th century. Initially developed for the military during the fiery forge of World War II, commercial aviation quickly built upon those advancements to transform global air travel. Not only can jet-powered planes fly further and faster, but they are actually mechanically simpler and offer a smoother and quieter ride than a propeller plane.

The immense power potential of the jet engine has led to the continuous evolution of high-speed airplanes like the Concorde and enormous jetliners like the double-decker Airbus A380 “Superjumbo.” The superior design qualities of turbines compared to piston engines have even made flying the safest means of transportation in the world.

Many innovative new ideas have come and gone in the last 100 years, but none have overshadowed the creation of the jet engine as we know it today. Engineering has advanced dramatically from the first jets that served the desperate twilight days of the Third Reich’s Luftwaffe to the colossal General Electric turbofans of planes like the Boeing 777X today. Yet the basic concepts and principles remain the same.

The Dawn Of The Jet Era

The de Havilland Comet was the first airliner to carry passengers in a jet-powered aircraft. The Comet flew in 1952, more than two decades after Sir Frank Whittle patented his design in the United Kingdom and 13 years after the Heinkel He 178 took flight powered by the first operational jet power plant. It wouldn’t be long before the Boeing 707 incorporated lessons learned from all of the earliest designs to create the template for modern jetliners, as they are still made today.

The 707 first took flight in 1958. It became the first widely successful airliner with jet power plants. That same airframe is still in service today with the US Air Force, as the number of its unique platforms is based on the 707 airframe. The very last commercial 707 wasn’t retired until 2013, standing the test of time thanks to the incredible engineering that went into every millimeter of the legendary plane. The DNA of the 707 can be traced to every single modern airliner with swept wings and turbofan engines mounted on pylons.

The rapid advance of jet engines led to the advent of high-bypass turbofan engines in the 1970s. The quieter and far more fuel-efficient engines made long-haul and affordable air travel a reality for the public and not just the military. The continued innovation of the commercial sector of jet engine design and engineering has seen it rise to equal or even surpass military technology in some aspects in the 21st century, with some new USAF platforms based on airliners like the 737 and 767.

Boeing’s Legendary 707

The Boeing 707 didn’t just popularize jet travel, it defined what a jet airliner should look and operate like, physically shrinking the globe and democratizing air travel for the masses. The 707 laid a foundation for aircraft design that has become universal and shaped the modern aerospace industry in many ways. Its successors, like the 737 and 747 “jumbo jet,” went on to push the aviation world forward not only in performance but continuously driving down the cost of air travel.

Just like the 707 was made for versatility, so too are its successors, with the 737, 767, and most famously, the 747 as Air Force One, all adapting for unique missions of countless varieties. While the industry has shifted toward more efficient twin-engine designs for long-haul flights, the 707’s four-engine layout set the standard for powerful, long-range transport and established the feasibility of intercontinental flights.

The legacy of the Boeing 707 is profoundly visible in every modern jetliner today. All modern high-speed airliners use swept wings, and the practice of mounting jet engines on pylons under the wings is ubiquitous thanks to the 707. The fundamental structure of modern airliners as a strong, cylindrical, pressurized tube was proven by the 707’s design. The 707 even established many of the fundamental control layouts and instrument configurations used in commercial cockpits, which have evolved into modern glass cockpits.

Jet-Powered Globalization

The advent of the jet engine powered a massive expansion of the global economy. The jet engine also broke down geographical barriers and fostered a more interconnected global culture. The concept of a “global village” has steadily grown to become more prevalent among the hundreds of nations and billions of people around the world, thanks to the far smaller perception of separation between humanity due to the ease of rapid air travel.

Jet aircraft delivered a smoother, quieter, and more vibration-free flight experience compared to piston-engine planes, which significantly increased the adoption of air travel as the norm for longer distances in the early years. Later, the significant reduction in operating costs and airfares from high-bypass jets made air travel accessible to the general public, which created a boom in international tourism that has never slowed down and only continues to grow in the post-Coronavirus era of commercial flying.

Air cargo services expanded globally, making it possible to transport perishable goods like fresh produce and pharmaceuticals across continents rapidly. The ability to move people and products across the same routes that once took weeks by sea in just a few hours by air is one of the most significant advances in human civilization. Jets fundamentally reshaped the concepts of time, distance, and geography.

Jets To The Rescue

During the weeks leading up to the final days, tens of thousands of people were evacuated from Tan Son Nhut Air Base using large, fixed-wing cargo aircraft. The C-141 Starlifter was instrumental in rescuing thousands, including many orphans, during Operation “Babylift,” which ferried children to the United States from the Philippines. The colossal Lockheed C-5 Galaxy, which had only just entered service, was also instrumental in this enormous humanitarian airlift.

Charter Boeing 747 and Boeing 727 jetliners were also used in the final commercial flights out of Saigon. The high speed and immense capacity of the early jet cargo planes and commercial jetliners facilitated the evacuation of over 50,000 people from the airport in April 1975 alone, making them critical in the overall humanitarian effort.

Another similarly massive scale air evacuation took place in 1991 when Israel and its national airline, El Al, flew military transports as well as 707 and 747 airliners into Ethiopia to rescue Jewish refugees. Operation Solomon airlifted over 14,000 Ethiopian Jews from Addis Ababa to Israel in a 36-hour window during the final days of the country’s civil war.

Beyond The Speed Of Sound

The proof that supersonic air travel could be an extremely impactful niche segment of the commercial air market. Despite its eventual retirement due to poor economic performance and noise pollution restrictions, its legacy lives on as NASA continues to explore “boomless” supersonic transport (SST) design. The next generation of Supersonic air travel is currently being forged by Lockheed Martin Skunk Works division and its X-59 prototype.

The advent of airliners flying beyond the speed of sound led to significant progress in numerous areas of aerospace technology, including material and aerodynamic design, but also avionics and navigation technology, including automation and fly-by-wire control systems. The Concorde project also served as a crucial learning experience in international engineering collaboration between the UK and France, which ultimately paved the way for the successful Airbus consortium.

Although the Concorde did not have the same profound, universal impact on globalization and aerospace as the Boeing 707, its unique and specialized contribution to the industry has helped advance numerous technologies that are now prevalent on aircraft of every type.

An Industry Built On Jet Power

By making air travel safer, faster, and eventually more affordable, passenger numbers quadrupled between the 1950s and 1970s. Today, approximately one-third of the world’s trade by value is transported by air. The entire aviation industry now supports over 86 million jobs worldwide and generates trillions in economic activity. The constant pursuit of enhancement and engine efficiency, reliability, and durability drives endless research and development in the industry.

The combined global total of the aviation industry’s economic value is estimated at 3.9% of the world’s gross domestic product (GDP), according to Aviationbenefits.org data. If the aviation industry were a country, it would rank 20th by GDP. The organization claims that by 2043, global air transport will support 135.4 million jobs and contribute $8.5 trillion to the global economy. The intense competition between manufacturers and airlines drives continued investment in new ideas to support innovative concepts.

The Evolution Continues

The far-reaching impact of technology developed for the purpose of the aviation industry has impacted many other sectors of industry and life, like energy production and computing. In the 21st century, the exponential advances of electronic and digital technology have marched in lockstep with progress in the aerospace industry, the two fields directly uplifting one another.

The next potential watershed technological advance in the aerospace industry that could equal or overshadow the jet engine is likely the move towards zero-emission propulsion systems. Airbus and other companies are heavily investing in hydrogen as a clean aviation fuel, with concepts for zero-emission aircraft that could enter service around 2035.

The expansion of artificial intelligence (AI) and the push toward autonomous aircraft could fundamentally change flight operations, safety, and pilot roles, potentially leading to fully autonomous commercial flights in the future. The jet engine will remain among the greatest achievements in the history of aviation, but the next great leap forward may well be on the horizon.