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Google’s self-driving car project has hired another senior leader in a sign that, just maybe, it is inching its way to becoming a stand-alone company and an actual real-world thing.

Shaun Stewart, Airbnb’s global head of vacation rentals since 2014, is now the director of Google’s driverless car initiative. He’s stepping in after Chris Urmson, the technical lead on the project,* suddenly departed two weeks ago.

Reuters first reported the hire. A rep for X, the Alphabet garage that houses the car team, confirmed it.

Stewart will be reporting directly to former Hyundai executive John Krafcik as the company prepares to take its years-long project to market. Krafcik was tapped to be the self-driving car project’s CEO in 2015.

It’s an unusual hire — bringing into the robotics projects someone who has primarily worked in the online travel industry. But X has brought in unconventional leaders before. And Stewart’s background — he was an exec at Jetsetter, a luxury travel site that sold to TripAdvisor — suggests the car team is pinning down a viable business model.

That is something many in the industry say the team has taken way too long to do.

If Google X takes an Airbnb-like online rental approach, it won’t be the only outfit going down that path.

Nick Sampson, the head of research and development at Faraday Future — Tesla’s purported rival — talked about exploring a “subscription model” when the company unveiled their concept car at the Consumer Electronics Show in 2015. In that model, Sampson said, consumers who paid for a subscription could order the vehicle type of their choice on demand as needed.

* An earlier version of the article said that Stewart was replacing Urmson. That is not the case. We regret the error.