The airline’s pilot facility in Brooklyn

Air Company

In a gray building tucked into an industrial corner of Brooklyn, New York, Stafford Sheehan Shows me a pot full of black metal pellets. “It’s a special sauce,” he says. They don’t look like much, but they say they could help produce billions of liters of fossil-free liquid fuel.

Sheehan’s startup, Air Company, is one of them. A growing set of manufacturers Attempts are being made to use captured CO2 to replace products made from fossil fuels, which can help reduce emissions. But…