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 ergonomic product,” says Edmond Huot, chief creative officer at Forward Studio, a global-branding firm in New York that helps airlines craft fresh approaches for discerning clients.

The new business class is coalescing around a simple idea: Make the cabin feel more like a sanctuary where intuitive design and fine details set the ambiance.

That thinking shows in United Airlines’ new Polaris Studio, debuting next year on Boeing 787-9s. The suites are 25 percent larger than the current standard, with sliding doors and an ottoman so a companion can join for osetra caviar and Champagne Laurent-Perrier Cuvée Rosé. Even the center seats have dividers that lower to bed height for shared time.

Huot notes that airlines must appeal to psychology as much as comfort. “Travelers not only expect privacy, but also a choreographed and elegant experience,” he says. “It should feel ceremonial, in a way.” And, in some cases, convivial. Qatar Airways’ Qsuite Next Gen converts from a private suite to an open social area, with a central configuration for groups of four and companion suites along the windows. Thoughtful design touches include stowable O.L.E.D. screens, larger dining tables, and, in a white-glove flourish, the “Make My Bed” turndown service.

Air France, for its part, is undertaking a full-cabin makeover that adds business-class suites clad in sumptuous full-grain French leather. Flying in one of these revamped pods late last year was unusually comfortable, and the sheer amount of space—particularly in the bulkhead row—rivaled first class on other airlines. That extra real estate is most useful for sleeping, since it allows for something closer to an actual bed than a narrow seat. Michelin-starred chef Daniel Boulud has crafted a seasonal menu that will be available on every Air France flight departing from the U.S., starting in November.

Set to launch later this year, Riyadh Air will debut a 28-seat business-class cabin in a palette of indigo, lavender, mocha golds, and stone accents—its aesthetic loosely inspired by a Bedouin tent. The design blends inviting ergonomics and luxe touches such as a 32-inch 4K O.L.E.D. screen (in Business Elite) and 52-inch-high privacy walls. “We want a modern-day version of Pan Am at its height, like Leonardo DiCaprio in Catch Me If You Can, but with a modernistic twist and obsessional level of detail,” says Tony Douglas, Riyadh Air’s C.E.O. “We want to bring back grace, beauty, and charm.”

Turkish Airlines is pursuing its own upscale vision with Crystal Business Class suites featuring marble-style tables, rose-gold finishes, and local leathers and fabrics. Add in the airline’s singular dining service—where a chef in a white coat and toque serves each suite—and it’s easy to see why chairman Ahmet Bolat calls it “an unparalleled experience above the clouds.” Biased, yes. But at 35,000 feet, rarefied business class isn’t just indulgence. It’s strategy.