Air Lease wants Boeing's New Mid-market Airplane to be designed as a technology platform capable of being updated over decades with new technology or a one-pilot cockpit.
The aircraft lessor's executive chairman Steven Udvar-Hazy also wants the NMA to have a choice of engine options – an opinion divergent from that of engine makers.
"This airplane has to have a long run" of 20 or 30 years, Udvar-Hazy said on the second day of the Paris air show. It must therefore have "features that will be [able]… to adapt".
For instance, he says, the NMA should be designed with an eye to the possibility of eventually converting the aircraft's cockpit to have just one pilot.
In such a configuration, automated systems or a ground-based pilot could support the pilot in the cockpit, he adds.
With regards to the number of engine suppliers, Udvar-Hazy says he has told Boeing he'd like a choice.
"I ask them to look at the A320 and the success that has had with a choice," he says, adding the ultimate decision will be driven by the forecast size of the overall market.
"I know the engine makers want it to be single-source," Udvar-Hazy says.
Indeed, on the first day of the show GE Aviation chief executive David Joyce said affiliate CFM International would make only a sole-source bid.
"The size of the market, we don't think, supports the investment for two engine manufacturers to split that market and try to get any kind of recover on that investment in a timely fashion", says Joyce.
His understanding is that the other NMA bidder, Pratt & Whitney, will seek similar terms.
Udvar-Hazy's comments reinforce his already stated believe that a clean-sheet aircraft is best suited for filling the middle-market niche, a category in which Boeing's 757 and 767 have sat uncontested.
Also on day one of the show, Air Lease chief executive John Plueger argued that the ideal middle-market replacement was a two-variant aircraft family, with the smaller variant carrying about 200 seats and the larger holding about 270 seats.
Those are the specifications Boeing has targeted with its proposed NMA. Udvar-Hazy has long advocated that Boeing develop the aircraft.
"The 5,000nm range, which is about average right now for the NMA, seems about right. Two variants also seems about right on the middle of the market," says Plueger.
On 17 June, Airbus announced it had squeezed more range out of its A321neo, launching a new variant called the A321XLR. That aircraft will carry around 200 passengers in three classes – fewer than the NMA – but its 4,700nm (8,700km) range places it squarely in the NMA's niche.