Boeing’s answer to the Airbus A350-1000 at the Dubai air show two years ago was to preach patience. The 11-frame extension of the A350-900 still seemed barely defined in late 2011, and had only 62 customers. Boeing had just released the 787 into operational service and only four months had passed since the launch of the 737 Max.

Several prominent analysts and – not least – past airline customers publicly urged Boeing to move faster, but the message from Seattle was clear: what was the rush?

Jim Albaugh, chief executive of Boeing Commercial Airplanes then, speculated to reporters in Dubai two years ago that Airbus would likely delay the A350-1000's entry into service again to 2018, after already postponing its arrival from 2015 to 2017. Boeing will “have a 777X come out not too long after that”, Albaugh said.

Two long and eventful years have passed since Albaugh’s prediction. Airbus, however, has kept the delivery date of the A350-1000 firm in 2017. Boeing also has not budged from the schedule that Albaugh only hinted at two years ago, and the first 777-9X is now scheduled to enter service in 2020.

The time for Boeing to formally answer the A350-1000 with a real product instead of a promise has finally come. Officially, Boeing still only says the 777-9X and the 777-8X will be launched by “the end of this year”, a timeline that makes the Dubai air show the logical venue for the announcement. This is as a coterie of Middle Eastern and Asian carriers line up to sign what Boeing has predicted could be a spectacular order haul.

“We could exit this year having launched two new widebody airplanes, the 787-10 and the 777X, two versions,” Boeing chief and chairman Jim Albuagh told analysts in mid-September. “One has already had a very strong launch. One has the potential for an extremely strong launch as well.”

The “very strong” launch of the 787-10 at the Paris air show netted up to 102 provisional orders from five customers, all of which are now firm except for British Airways' commitment for 12 aircraft. An “extremely strong” launch for the 777X could as much as double that number in Dubai, if numerous reports before the show are accurate.

For months, Boeing’s deliberate – some would say slow – pace to define and launch the product that will replace the flagship 777-300ER and sidekick 777-200LR created ripples of discontent.

Boeing’s patience may yet produce a worthy successor, but it is game time for Airbus to build momentum in the market. Airbus exploited the two-year gap wisely. Support for the A350-1000 reached a new peak on 7 October, the day that Japan Airlines signed an order to buy 31 A350s, including 13 of the -1000 variant. It was the first time that a Japanese carrier had purchased an Airbus widebody in two generations.

The A350-1000 also attracted other major customers during the interim, including an order by the IAG Group for 18 A350-1000s signed on 25 September and another by United Airlines for 35 during the Paris air show.

Despite the progress of the Airbus rival, Boeing’s more patient and measured approach on the 777X could still work in the manufacturer's favour. The A350-100 now has 176 firm orders on backlog after six years on the market. One week later in Dubai, Boeing has an opportunity to exceed that number with the 777X family.

When Boeing revealed the first public draft of the dimensions and performance of the 777X family at the Paris air show, the strategy seemed clear. With the A350-1000 normally seating about 350 and the A380-800 accommodating more than 490, Boeing has positioned the 360-seat class 777-8X and the 400-seat class 777-9X in between – at the lower range. The airframer was also careful not to overlap too plainly on the high end with the normally 406-seat 747-8I.

The cross-section of the 777 is maintained, but the interior cabin shell is “scalloped” at shoulder height to accommodate 10-abreast seating at a less than 18in seat width. The cross-section decision provides Airbus with an easy talking point on the seat density of a long-haul aircraft. At the same time, keeping the 777 fuselage intact saved Boeing the trouble of recapitalising the aircraft’s entire supply chain, as the company was forced painfully to do when it replaced the seven-abreast 767 with the eight-abreast 787.

The keys to the 777X’s performance are replacing the General Electric GE90 engines with the GE9X, and exchanging aluminium alloy with carbonfibre reinforced plastic along an extended, 71.3m (234ft) wingspan, including making the last 3.35m of each wingtip foldable to accommodate all of the same gates and taxiways as the 777-300ER.

The preliminary specifications released in Paris were then subject to negotiations with a wide range of potential customers. The possibility of so many of the largest orders concentrated in the Middle East could still prove to be influential in tilting the design and underlying technology.

An example is perhaps the GE9X engine. It is already revealed as an ambitious project, costing GE billions to develop over the next five years. It will include the first application of ceramic matrix composite (CMC) in the blades of the high-pressure turbine and the combustor liners. It will also use the material in the shrouds around the first stage turbine, following the example of the CFM International Leap-1 engine series.

More recently, another new technology has been proposed for the GE9X: water injection. In an interview with Flightglobal in October, Emirates chief executive Tim Clark said the GE9X may require water injection as a supplementary cooling system to operate in Dubai during the hottest months. Although GE initially appeared to reject the idea when asked about Clark’s remarks, the company has softened its message.

In reality, GE has been developing water injection systems for turbine engines for more than a decade. It has developed several derivatives of aviation engines for industrial power turbines, including the LM6000. In 1998, the company introduced the Sprint spray intercooling system for the LM6000.

The Sprint system includes 23 injection nozzles attached on the engine front frame, which sprays a mist of water to cool the airflow as it enters the high-pressure compressor. The airflow is therefore cooler as it enters the combustor. GE credits the system for increasing the power of the LM6000 by 9% in normal weather and by 17% on hot days.

It would not be the first time that GE has applied technology to an aircraft engine that was first introduced and matured in the more benign environment of a ground power unit. CMC materials, in fact, have been used widely in GE’s industry gas turbines for several years, but are only now finding their way into aviation applications.

Although the engine of the 777X contains several new technologies, the programme itself is actually considered to be a conservative investment within Boeing. The aluminium fuselage, conventional electrical system and even the composite wing are all technologies that Boeing now believes, understands and can execute without the drama associated with the 787 development.

Boeing conceded the first-mover advantage to the A350-1000. It is also trying to satisfy a wide range of needs for a large widebody in two variants that seem tailored to meet the special needs of only a few of the largest customers. The 777X is promising airlines another 20% savings in fuel consumption compared with the aircraft it replaces, and it may be all that Boeing needs to extend the 777 franchise for at least another 15 to 20 years.

“If we are making new airplanes that were 5%, 6% better, you wouldn’t see this kind of robust demand. You would see people willing to hang on for another seven or eight years before they need another airplane,” Jim McNerney told analysts in September. “But it's all the bleeding edge stuff that we went through over the last 10 years that has now firmed up, whether it's composites, whether it's some new engine technology that had some hiccups, host of other things but it's beginning to pay off now.”