Fuel efficiency has been a critical topic in aviation for the last decade. It is a time of great change for the industry, with ambitious targets set to reduce the environmental impact of commercial air travel. The inclusion of sustainability initiatives, such as the introduction of SAF, CORSIA, and ETS, can only do so much - at least until increased production and reduced cost make SAF more palatable. Airlines must reduce their jet fuel consumption - and ensuring the aircraft in your fleet are as fuel efficient as possible is a key way of reaching those targets.
Of course, measuring fuel efficiency can be complicated. Each manufacturer points to different test conditions and factors, such as passenger count, baggage weight and capacity, flight length, and conditions. We’ve compared the latest commercial aircraft available today from the world’s two largest and most popular manufacturers based on fuel burn per passenger over a long-haul flight to bring you the top 6 most fuel-efficient models*.
The 787 ‘Dreamliners’ are currently in direct competition with the A350s - and the 787-9 is a formidable opponent. It comes out on top for fuel economy per seat In standardized industry testing, thanks to being the lighter of the two aircraft. However, it slightly lags behind the A350-900 in several key areas. None of these differences are very great, but for potential buyers, they may be what makes or breaks the deal.
Firstly, the 787-9 holds a maximum of 420 passengers, 20 short of the Airbus equivalent. Its maximum range also falls short - 14,140km compared to the A350’s 15,000km. Then there’s maximum take-off weight - 254,000kg compared with its rival's 283,000kg. Even fuel capacity is less, at 126,372 litres versus 166,488 litres.
But it’s not all bad news - both planes have almost identical cargo capacity and cruise speed, and based purely on fuel efficiency per aircraft mile, the 787-9 still comes out on top. Boeing has put sustainability at the heart of their future focus, as demonstrated by Virgin Atlantic using a B787 to become the first commercial airliner to fly transatlantic on 100% SAF.
And then there’s Boeing’s much-anticipated 777X series, due for release in mid-2025 - more on that later…
As one of the most popular long-haul wide-body planes on the market today, it’s easy to see why airlines have embraced the A350, especially the 900 model. With a standard layout of 315 seats and a max capacity of 440 passengers, it also boasts an enviable range of over 15,000km - or, if you opt for the Ultra Long Range (ULR) version, an incredible 18,000km, more than 20 hours non-stop.
Airbus claims these statistics are thanks to a ‘clean sheet‘ approach to aircraft design. This includes making the aircraft lighter, with 70% of the plane consisting of ‘advanced materials’, such as lightweight carbon fibre. The design has also been tweaked for efficiency, with redesigned wings for increased aerodynamics.
Then there are the engines - twin Trent XWBs, currently the world’s most efficient large aero-engine and possibly the standard for next-gen aircraft. Manufacturer Rolls Royce claims each turbine blade generates ‘the same horsepower as that of a Formula One engine’ - impressive, especially when you consider that they are also more efficient and even quieter than older engines.
Airbus may not be at the top of the table regarding stand-alone fuel efficiency, narrowly behind Boeing in standardized testing. Still, it’s very close - and with the 900’s enviable range and capacity, it’s no wonder it’s the current go-to choice.
Another wide-body option from Airbus, the A330-900neo may be a new plane, but it’s still based on a 30-year-old design. While still an excellent contender - especially in terms of fuel efficiency - the cracks begin to show when compared to ‘clean-sheet’ aircraft designs such as the A350 and 787.
Launched in 2014 at the prestigious Farnborough Air Show as a direct rival to the 787, the 330neo has shown significant improvements over the last decade - most notably by reducing fuel consumption and CO2 emissions by 25% over previous generations. It narrowly squeezes ahead of the pack for passenger capacity, at a respectable 460 maximum, and has advanced tech and aerodynamics such as new Trent engines and ‘composite winglets’ to reduce drag and generate lift. It’s also slightly faster than the 787-9 despite boasting higher fuel capacity.
However, that’s where the good news ends. Range, MTOW, and cargo capacity are all less than the 330’s competitors - and considering the 900neo is approximately $15 million more expensive than the 787, its appeal may be limited.
Despite being the smallest of the 787s, the B787-8 still packs a punch. It can hold fewer passengers, maxing out at 242 for a standard two-class layout or 406 maximum - no surprise given the shorter length of the plane. But its range exceeds that of its big brother, and it features new Rolls-Royce Trent 1000 engines.
Like its larger counterparts, the 787-8 frame is comprised of nearly 50% carbon fibre and other composite materials, offering significant weight-saving advantages compared to aluminium designs.
Ultimately, the B787-8 can fly further than some of its rivals - but at the cost of passengers and cargo capacity. Boeing claims the 787-8 is ‘the only suitable replacement for the A300, A310, 767, and A330-200’, and points towards an apparent trend of airlines favouring smaller aircraft for international routes. It falls short when it comes to fuel efficiency - but only when compared to the other super-economic options on this list.
Now, let’s look at the biggest of the wide-body aircraft on the market, starting with the A350-1000. These aircraft typically carry more passengers for a higher density, lower cost long haul option. But how does that affect fuel efficiency? Compared to their slightly smaller siblings, the A350-900 and the B787-9, surprisingly little.
Boeing still tops Airbus in a fuel efficiency comparison, but again, not by much. It’s the same story when it comes to passenger count too - the Airbus holds a maximum of 480 compared to Boeing’s 440.
But the real difference here is the range - the A350-1000 can go for 16,100km compared to the 787-10s 11,910 - a significant difference, and a likely reason why airlines may choose the Airbus over its rival.
That being said, there can be no argument that, on a per-seat basis, the B787-10 comes out on top of the equivalent Airbus. The question is, what is a more reliable way for airlines to save money?
One problem with focusing solely on fuel economy is the price of the fuel itself. The cost of aviation fuel is constantly in a state of flux, varying on a day-to-day basis. Add to this the possibility that airlines may have to continually increase the ratio of expensive SAF inclusion in their fuel mix, and the answer is less than clear.
For that reason - even though the 787-10 is the most fuel-efficient of the larger wide-body planes - consumers may think twice before committing.
Ultimately, the decision airlines must make on which aircraft to utilise in their fleet remains a difficult one, and the margins between each model on offer are minimal. Owners of any of the options listed here, whether they come from Airbus or Boeing, can rest assured that these aircraft are some of the most fuel-efficient money can buy. But is it worth waiting…?
We’re referring, of course, to the upcoming release of Boeing’s 777X series. Originally scheduled for a 2020 release, the latest offering from Boeing has been pushed back to 2025 - possibly due to some of the problems reported recently in the press.
But when they do arrive, they set to raise the bar even further, with even more passenger, fuel, and cargo capacity, and no doubt fuel efficiency. The question is, what will Airbus do to close the gap?
*All calculations estimated based on pre-existing research using assumed fuel temperature (15C), density (0.8kg/L), and passenger weight (190lbs).