Peter Carter has a prediction about the future of law firms—and it’s bold.

According to Carter, the executive vice president and chief legal officer at Atlanta-based Delta Air Lines, in 10 years, the firms that have figured out project-based billing are going to be the leaders. And those that are still sending invoices for billable hours will be left behind. “Accounting firms have figured out how to do this, consulting firms have figured out how to do this, investment bankers have figured out how to do this,” he says. “And so in my mind, I ask, ‘Why can’t lawyers?’”