In today’s premium cabins, the latest flex isn’t Champagne or caviar—or even a sliding door. It’s quiet luxury. Business class has been edging toward residential elegance for years, but on a recent long-haul flight ensconced in Cathay Pacific’s new Aria Suite, this trend felt fully realized. The details prove the point: The suite’s accent-light fixture could sit comfortably in a midcentury-modern living room (and can even be tuned to your ideal hue). Nearly every surface is textured and inviting to the touch—even the lie-flat bed is wrapped in ethically sourced wool—and storage cubbies close with the hush of bespoke cabinetry. “This is a space that adapts to travelers’ needs and feels effortlessly personal,” says Cindy Lam, Cathay Pacific’s senior vice president, Americas. The Hong Kong–based carrier isn’t the only one deliberately blurring the lines between business and first class. “Airlines are translating the cultural mores of providing more than just an..