A decade ago Delta became the first airline in the world to put closing doors on every business-class seat, and the Delta One Suites concept has aged well — it has repeatedly picked up the TPG Award for best U.S. airline business class, and the enclosed-pod format has since spread to Qatar Airways, British Airways, Virgin Atlantic, ANA and Air France. If you're eyeing one of these suites for a long-haul trip, the catch is that not every Delta widebody has them, so it pays to check which aircraft is operating your flight before you book.

The genuine door-equipped suites fly on the Airbus A350-900 and A330-900neo. The Boeing 767-400ER got a refresh that brings the same seat footprint and finishes, but without sliding doors. Delta's older A330-200s, A330-300s and 767-300ERs still lack suites entirely, though refits of the A330 fleet were underway at the time of reporting, and an all-new Delta One Suite design is promised for the A350-1000s arriving from 2027 — the largest cabin yet, with 53 suites. Cabin sizes vary: roughly 32 to 40 suites on the A350, 29 on the A330-900neo and 34 on the 767-400. These jets mostly serve routes from Atlanta, Detroit, New York JFK, Los Angeles, Minneapolis, Salt Lake City and Seattle to Africa, Asia, Europe and Australia, with 767-400s favouring shorter East Coast–Europe hops.

Onboard, the staggered 1-2-1 seats convert to fully lie-flat memory-foam beds. The A330-900neo versions are the roomiest at 22.5 inches wide and up to 80 inches long in bed mode; the A350 and 767 are around 20 to 20.5 inches wide. All have 18- to 18.5-inch touchscreens, power outlets and fast Wi-Fi, plus Missoni bedding and amenity kits with Grown Alchemist skincare, menus from chefs like José Andrés and wine curated by sommelier Andrea Robinson served on Alessi tableware. One quirk: some configurations have only two business-class lavatories, so lines happen.

For seat picks, the "true window" seats (alternating rows, window-side) have their wide armrest on the aisle for maximum privacy, though aisle-side window seats are easier to get out of and the door covers privacy anyway. Travelling as a pair? Take two centre seats — there's a movable privacy screen, but no cosy "honeymoon" row like on some airlines. Steer clear of seats near galleys and lavatories, such as row 1 on the A350, 8A on the A330-900neo and row 9 on the 767.

Booking with miles is the tricky part. Delta switched to dynamic pricing, and long-haul suite awards routinely run 125,000 to a jaw-dropping 800,000 SkyMiles each way. Genuine bargains exist — saver-level awards to Europe have appeared from 115,000 miles, and Seattle–Taipei tends to price below other transpacific routes. Use Delta's five-week flexible date calendar, filter for nonstops on suite-equipped aircraft, and check Seats.aero to scan the calendar. Partner options include Virgin Atlantic Flying Club and Air France-KLM Flying Blue, both transferable from every major points programme — just note that Flying Blue partner availability is scarce and adds fuel surcharges. SkyMiles transfers 1:1 from Amex Membership Rewards.

Worth knowing before you commit: several Europe and South America routes still use planes without suites, so verify the aircraft type at booking.