The Propeller Is Making a Comeback in The Pursuit of Greener Air Travel

The propeller — a relic from the dawn of powered flight more than a century ago — is making a comeback as an emblem of aviation’s greener future.

Rotors are proliferating on futuristic air taxis and plane prototypes powered by hydrogen and electricity. The old-school feature is also central to a radical new engine that could one day replace the turbofans on today’s jetliners as climate change pushes the industry to innovate its way out of fossil-fuel dependence.