As aviation struggles to emerge from the historic, pandemic-driven downturn, another longer-term challenge already looms. Concern about air travel's contribution to climate change threatens to curtail growth of an industry that has expanded steadily for decades, shrinking the world for travelers and connecting the global economy.
The airline industry, contending with growing political pressure in Europe and recently even in Seattle for new restrictions on flying, this month formally committed to a target of "net zero" carbon emissions by 2050.
To achieve that, governments and industry will have to invest billions of dollars in infrastructure in the coming decade. Further out, Boeing and Airbus will have to develop dramatically new airplane designs.
For the flying public, all outcomes in the years ahead point to an increase in the cost of flying.
Yet that distant net-zero emissions target is so radical, and the proposed technology solutions so uncertain, that aviation risks falling far short.
Airbus CEO Guillaume Faury recently warned that if the industry's new push for climate sustainability fails, governments could force a reduction in air travel by banning some of the flying that is routine today — a major step back after more than 100 years of passenger flights.
"Aviation has a very important role on the planet to connect people and to contribute to prosperity," he said at a two-day aviation sustainability summit convened by Airbus in France last month. "We are at a point where this is in danger if we don't manage to transition and succeed in the decarbonization of the sector."
This is "the number one matter of discussion in the industry, even more than COVID now," he added.
Under pressure, the world's major airlines have firmly committed to one key technology that will dominate aviation's environmental push in the coming decade: Sustainable Aviation Fuel, or SAF.
For the plane manufacturers, the major costs and big risks will come later.