Norwegian's order on 25 January for 222 Boeing and Airbus aircraft shows how close the contest for re-engined narrowbody supremacy between the 737 Max and A320neo has become.
The deal, which includes firm orders for 100 Boeing 737 Max aircraft and 22 737-800s, as well as purchase rights for another 100 737 Max, is Boeing's largest ever in Europe. Norwegian is also the first European carrier to finalise a deal for a member of the 737 Max family, in this case the 737-8. It also signed an MoU for 100 Airbus A320neos.
Order figures for the two aircraft families are now rapidly converging: Boeing boasts of "over 1,000 orders and commitments from 15 customers" for the Max, while Airbus, at 31 December, had 1,256 firm orders for Neo-family aircraft (although that figure does not include the Norwegian MoU and several other commitments).
Both airframers can take satisfaction from Norwegian's spending spree. Boeing argues the order represents a significant endorsement of the Max and helps it claw back lost ground against the Neo. However, with Norwegian a loyal Boeing customer - its 62 in-service aircraft are all Boeing 737s and it has an additional 62 Boeings on order - the contest was Seattle's to lose.
To that end, Airbus can claim a partial victory with its entry into Norwegian's fleet, having already secured a strong presence in Sweden and Finland.
Norwegian chief executive Bjorn Kjos explained the order split by pointing out it was now sufficiently large to order from both manufacturers to ensure capacity and encourage competition.
However, analyst Richard Aboulafia of Virginia-based Teal Group, suggests Norwegian's split order shows that airlines are keen to hedge their bets with regard to the vastly different technologies employed in the new powerplants on offer.
The 737 Max will be powered by the CFM International Leap-1B, while the A320neo offers a choice of engines between the Leap-1A and the Pratt & Whitney PW1100G geared turbofan. Norwegian is yet to reveal an engine selection for its Neos.
"It goes to show that the hedging by [ordering] Airbus and Boeing, is more about hedging the engine choice," said Aboulafia.
"I've never seen so much divergence in engine design and that would make me want to hedge my bets if I was a fleet planner."
Although CFM is promising a custom core for the Leap-1B, in part to compensate for the smaller fan size necessitated by the wing height of the 737, Aboulafia said the manufacturer faces significant challenges to match the performance of the larger-fanned Leap-1A and PW1100G.
The 737 continues to gain momentum, however. Southwest Airlines' December order for 150 737 Max, with an option for 150 more, represented a major endorsement for the programme.
"I think as long as Boeing can maintain the momentum it is very positive news. It should be their year to get back on track with a large number of Max orders."
Southwest is another Boeing stalwart, however, so its decision to choose the Max was no great surprise. Aboulafia believes it will only be when a carrier like Delta Air Lines, which has a significant in-house MRO and technical capability, picks either aircraft that a clearer picture of the market emerges.
Engine development will be the key factor though, said Aboulafia. Although "Pratt and Whitney seems somewhat further ahead" with its development of the PW1000 range, CFM "has a fairly straightforward and compelling story", albeit it is a "long way from having something tangible".
"They aren't flying their engine round on an A340 test-bed like Pratt is," he said.
For its part, Norwegian is comfortable with the size of the order. Kjos said: "We have secured our fleet renewal for years to come and, as we intend to replace every aircraft after seven years of operation, it is mandatory that we plan at least 10 to 20 years ahead."
The market conditions are right for orders from both manufacturers, he believes. "When there are tough market conditions, fewer airlines are ordering aircraft, so you have good negotiation possibilities if you do order," he said.
Norwegian expects deliveries to commence in 2016 and said it will focus on growing its business in Europe, with some of the new aircraft placed at its current bases. The carrier opened a base in Helsinki last year and will open a base in Malaga, Spain, in March and further bases outside its home country are planned, Kjos confirmed.
The airline will add more destinations, but also more frequencies in the markets in which it currently operates.
This ambitious expansion suggests it is preparing a serious assault on its struggling competitor Scandinavian Airlines (SAS). SAS has 132 active aircraft in its fleet and 35 aircraft on order, but it has not made a full-year profit since 2007.
However, Norwegian played down thoughts of Scandinavian dominance. "We have no intention to become the 'largest' player for Scandinavia," said Kjos. "Our organisation is focused on delivering a good product to our customers."