In addition, Airbus will have some other challenges on its hands. Last year's announcement at the Paris air show about revising specifications for the A350-1000 was not well received by airlines. Since then, the aircraft maker has seen the backlog for the largest member of the A350 family shrink. Airbus has argued that the airlines are getting a better product, even if at the cost of a two-year delay, but so far, customers are reticent. John Leahy, chief operating officer for customers, insists that will change. At Farnborough, he will have a chance to see whether his efforts at convincing airlines are gaining traction.

Booking further orders for the A380 also will be on the agenda. Airbus has seen only slow progress in building up its orderbook for its flagship product of late, and with plans to deliver at least 30 aircraft this year it is trying to secure at least that many orders to avoid its backlog shrinking. Eight airlines now operate the A380; Malaysia Airlines, the latest airline to receive its first A380, is due to showcase the aircraft at Farnborough.

Few doubt that the most intense battle will be the A320NEO versus the 737 MAX. Airbus enjoys a huge market share lead over Boeing, which even the European aircraft maker itself does not expect to last at current levels. But Leahy has thrown down a challenge to Boeing, saying the NEO will have a long-term market dominance of 60% in the sector. This year, though, he expects the MAX to garner more deals than the NEO. To some extent, the more important near-term challenge for Leahy is to sell the vacant delivery slots for A320 classics to ensure a smooth product transition to the NEO.

There are still more details to come for the MAX. Boeing's design has evolved in recent months, with the revealing of a new winglet and the gradual increases in fan size. Airbus is touting NEO's much larger fan, but MAX's backers note that the Leap-1—the only engine offered on MAX 737—may have a smaller but lighter fan to make up for the smaller bypass ratio. The war of words over which aircraft is the more fuel-efficient is already underway. It is possible Boeing will book its 10,000th 737 order at the air show.

In the defense realm, there will be far fewer signs of optimism. The degree of austerity that companies are grappling with is perhaps best illustrated by Northrop Grumman's decision to forgo Farnborough entirely. In an era of shrinking defense budgets in the U.S. and Europe, attending an expensive event in an increasingly narrow market had to be weighed against focusing on growth areas such as the Middle East and Asia.

As domestic markets diminish for much of the industry in the West and the focus shifts to exports, the battle for foreign deals is becoming more intense.

Indirectly, that sentiment too will be reflected at Farnborough. Even though the U.K. is due take delivery of its first F-35B short-takeoff-and-vertical-landing aircraft next month, do not expect the Joint Strike Fighter to be in the forefront. Interestingly, this is not because of the government's high-profile flip-flop—from the F-35B to the F-35C then back to the F-35B. Instead, U.S. officials indicate that London wants the focus to be on the Eurofighter Typhoon, even though BAE Systems is a major JSF program partner. Pressure is mounting to secure more foreign sales for Typhoon in light of recent contract award defeats in Switzerland, India and Japan. There seems to be a sense that the Farnborough stage is not big enough for both fighters.

But the Typhoon program recently received some good news. The U.K.'s latest spending plan includes funding upgrades, not yet spelled out, for the multi-role combat aircraft.

Even if the JSF is downplayed, Typhoon will still have to share the fighter limelight at Farnborough. Saab is bringing its Gripen demonstrator and, in a game of one-upmanship, the Gripen will be equipped with the Selex Galileo Raven ES05 active, electronically scanned array radar (AESA). Typhoon will not fly with its AESA until next year, nor is government funding expected to underpin the development until that time.

The air show could also provide the stage for the newly elected French government to signal whether it will continue with the Anglo-French defense security cooperation effort. As part of that pact—agreed upon by then-French President Nicolas Sarkozy before he lost the election to Francois Hollande last month—France and the U.K. had begun working cooperatively on a medium-altitude long-endurance unmanned aircraft program, and have paved the way to potentially doing the same for unmanned combat air vehicles. Whether Hollande will follow that path is still uncertain.