PARIS—If there is one thing that players in the long-haul low-cost sector agree on, it is that there is a market for such services.

But as became clear at the Paris Air Forum, an industry gathering held here on the eve of the Paris Air Show, executives disagree on what markets exactly they should serve and what aircraft they should fly.

“Big routes with big aircraft will be the focus,” said Marc Rochet, CEO of Orly-based long-haul LCC Frenchbee.

“You have to go into the large catchment areas,” Norwegian CEO Björn Kjos said. And because they are often slot-constrained, operating larger aircraft is the better choice in Kjos’ opinion rather than betting on long-haul capable narrowbodies such as the Airbus A321LR or the soon-to-be-launched XLR.

JetBlue CEO Robin Hayes, by contrast, believes that there is “a tremendous amount of opportunity with lots of unserved routes in Europe” that his airline could enter with the A321LR.

Executives from Norwegian, Frenchbee, JetBlue and International Airlines Group (IAG) subsidiary Level stressed that the segment they are trying to build is promising. “Some will be very successful, some will have to fight,” Rochet said. “You definitely have to do something new in the cabin, in marketing and sales ... even if the demand is there not all routes will work.”

Rochet’s Frenchbee is growing an Airbus A350-900 fleet and takes about one additional aircraft per year. The key, Rochet said, is high cabin density and high utilization. “We went about 5,000 hours per year. If you are below you cannot make money,” he said. Rochet also highlighted that the network has to be aligned to changing traffic flows and seasonality, therefore not only flying East-West, but also North-South. The airline currently has one A330-300 and two A350-900s, a third A350 is to be delivered soon.

Kjos pointed out that it is “incredibly difficult to make it work without a feeder network” although Rochet disagreed saying “I don’t like feeding too much—it is adding costs.” The two airlines are in different strategic positions as Frenchbee has the advantage of being based in Paris, one of the largest origin and destination markets in Europe, whereas Norwegian’s network is broader.

The Norwegian CEO said that he would never have taken the risk of building up a long-haul LCC in Iceland such as WOW Air, which ceased flying earlier this year. Primera Air, another failed carrier, was “sub-scale” in his opinion.

The proposed A321XLR, widely believed to be launched at the Paris Air Show, is being met with high interest in the sector. “There is no one who has not looked at it,” Level’s Vincent Hodder said. He believes the aircraft could be a “fundamental gamechanger on the transatlantic market” with range for up to ten hours of flying. The aircraft, being a narrowbody, would also make it easier for LCCs that started on short-haul routes to enter long-range flying. Level sees it complementing larger aircraft like the A330-200 that it flies from Barcelona to Santiago, Chile.

Even Rochet, who favors large aircraft, sees a role for the A321XLR in existing networks when it comes to adjusting capacity downwards in the low season. He would, however, not use it as an airline’s sole long-haul aircraft.

Kjos pointed out that in slot-constraint markets such as New York or London it makes more sense to fly larger aircraft to maximize the use of scarce airport capacity, therefore narrowbodies should be deployed to smaller catchment areas.

Hayes said JetBlue has looked at the A321XLR but is sticking to the A321LR as it launches European services to London. The aircraft, with around 600 nm more range, would allow JetBlue to fly deeper into Europe, he said.