An international flight that leaves from a train station

Imagine if instead of boarding your plane at the airport, you could hop onto a train at a nearby railway or light rail station. The train would travel to the airport, where the passenger compartment would be transferred and clipped beneath a flying wing just before it takes off.

ABU DHABI // Could aviation change so radically from the way we know it? History suggests that in the future it will look very much like it does today, with ever larger, faster, and stronger airplanes. While improvements in engines and materials have led to a steady increase in performance, the basic concept underlying commercial aviation has hardly changed since the end of the Second World War.

Today we are reaching the technological limits of this incremental approach, prompting European and American aircraft manufacturers to study unconventional aircraft designs. But what if, instead of redesigning the airplanes, we redesigned the entire concept of commercial aviation?

On paper and on the computer, a team of researchers including several Master's and doctorate students, one of them associated with EPFL Middle East, conceived and developed Clip-Air, our vision of a new modular aircraft, which we recently presented at the Paris Air Show in Le Bourget, France.

The idea behind the design is to split an aircraft into two components: a flying wing equipped with engines and landing gear on the one hand, and capsules that can be clipped under the wing on the other. The capsules could carry passengers, freight, or fuel.

The concept opens the door to a slew of alternative ways to redesign - and improve - the performance of the aviation industry and global transportation.

Modularity, and the flexibility that comes with it, has many other far-reaching consequences. Separating passenger compartments from fuel reservoirs and decoupling them from the cockpit could increase safety.

Fuel consumption per passenger would drop, as our calculations show that one wing could carry the same number of passengers as three A320 airbuses.

And transporting freight when flight occupancy is low would keep empty return flights - common in the industry today - to a minimum.

Clippable capsules also open the door to the exploitation of renewable energy sources to power the plane's engines. Liquid hydrogen tanks, for example, could be prepared in advance in specialised facilities and clipped under the wing to power motors, pushing carbon-neutral aviation into the realm of feasibility.

What is innovative about Clip-Air is the concept, not the technology used. Our studies have shown that the concept could be put into practice using today's technology.

More importantly, since it behaves just like a normal plane, an aircraft based on the Clip-Air design could be used in today's airports.

Then, over time, the infrastructure could be upgraded to connect the airport to the railway network and further exploit the modular design.

Whether or not Clip-Air catches on, it will spawn research in a wide range of fields. Architecture students have already designed airports tailored to these new modes of transport, and mathematicians are developing models to streamline operations in these envisioned facilities.

Its interdisciplinarity is what makes it such an interesting project in the university setting, where researchers from all the walks of science interact and put their minds to shaping the way we will live in the decades to come.

- Prof Michel Bierlaire is director of the transport and mobility laboratory at EPFL in Lausanne, Switzerland. The Clip-Air project is presented on clipair.epfl.ch.