Snecma's aircraft engine assembly hall at Villaroche, south-east of Paris, is the size of a sports stadium and eerily quiet.
To the murmur of transistor radios, on production lines half a kilometre long, technicians work with a steady efficiency, building up the complicated web of pipes and wires that surround the jet engines' bodies.
Villaroche is one of the best places in the aviation world to be right now, because the plant is due to produce the new, fuel-efficient turbofan CFM International LEAP-X engines, which both Airbus and Boeing have decided to use on their new-look narrowbody planes, the A320neo and the 737Max.
Nearly 2,000 of these engines have been ordered, enough to fill Snecma's order books for the next seven years.
"Their decision has been to re-engine, to answer the market's need for planes which are very robust in the face of high fuel prices," says Snecma's head of new commercial applications, Olivier Longeville.
"The key decision was to help the airlines by buying in some brand new engines, which can be installed on planes quickly."
Airbus decided late last year that it would offer the airlines a new type of A320, consisting of the existing airframe with new engines fitted on. The A320neo will burn up to 16% less fuel, Airbus insists, and it soon received orders for 1,000 the new planes.
Late this summer, Boeing also decided to abandon any considerations it had with regards to remodelling its 737, which is the A320's main rival.
The project would have taken until 2020, so instead Boeing will re-engine its plane as well.
The new 737Max will be available from 2017, while the A320neo will be available from 2015.
Boeing will use the Leap engine on all its 737Max aircraft, while Airbus will offer customers the choice between an A320neo fitted with Leap engines or a version fitted with Pratt & Whitney's newly- developed engines.
Snecma and US engine-maker GE have joined forces to create the Leap engine, with each holding a 50% stake in CFM International, which has spent $2bn over the past decade developing the technology.
"We have revolutionary new fan-blades made of composite materials, which are lightweight and extremely resistant to damage from such things as bird strikes," says Francois Bastin, programme manager for Leap.
"Another new technology is the high-pressure, high-performance core. Today, performance on fuel burn is key to our customers, so we have developed a new generation of high-pressure core, which is more efficient."
The aircraft manufacturers and the engine-makers are telling the airlines that with the 737Max or the A320neo, they can make annual savings of $7m on every plane.
Inevitably, however, Boeing and Airbus are squabbling over which plane will be the most efficient. Boeing claims a 4% advantage for the 737Max, which Airbus vehemently denies.
One question is how CFM International will build a fully-efficient Leap engine for the 737Max.
Engines can be given extra thrust, and therefore more fuel efficiency, by increasing the diameter of their fan-blades.
But the wings on the 737 are set close to the ground, so there is very little space underneath them for fitting an engine with longer fan-blades.
An engine with a larger diameter could be fitted to the 737's wing if set further to the front of it.
However, that might impede airflow.
Mr Bastin says CFM International is working on an engine that will compromise by having a slightly wider diameter and being set slightly further towards the front of the wing.
"You have to optimise," he says. "It's really about providing the best combination of wing, engine, and airframe. That's what we do for Boeing, and for Airbus."
Boeing's 737 and Airbus's A320 are two of the best-selling planes in aviation history. A such, the two dominate the global market for single-aisle aircraft.
It is forecast that over the next two decades, airlines will spend $2 trillion on planes in this category.
However, others have been muscling in on the lucrative Airbus/Boeing duopoly.
China's is offering airlines the single-aisle Comac, and Russia's Sukhoi is selling its 100 seat-plus Superjet.
That competition has prompted the two industry leaders to opt for upgrading their offerings through re-engining - rather than wait for totally redesigned aircraft.
"The entry of China and Russia changed the game," says Mr Longeville.
"But currently all the aircraft manufacturers seem to be finding a place in the market. Comac currently has 165 orders. Airbus has 1,000 for its new plane and Boeing has 600 for its new plane. So everyone has a slice."
Airbus and Boeing decided to re-engine their planes because they both believe it is cheaper, quicker and less complicated to do so than to develop entirely new models of aircraft.
For engine-makers such as Snecma, however, developing the new engines that do so much to improve the aircraft has cost billions of dollars.
They will be calculating how to earn that money back.
The sale of the new engines is one way of bringing in cash, of course.
However, much more is earned from charges for maintenance and spare parts over the lifespan of the engines.
"When you install an engine, you get a one-off fee," says Mr Bastin.
"But over the life of an engine - say seven, eight or nine years - you get a steady revenue stream from spare parts and maintenance.
"How much more that is is not public information. But the key point is that the revenue from spare parts and maintenance pays for the research and development for the next generation of engines. That is the cycle we work to in this industry."
The Dubai Airshow runs from 13 to 17 November 2011.