Boeing's upcoming 777X set to surpass Airbus A350 as widest passenger jet

When it entered service in 2015, the Airbus A350 XWB was only marginally wider than its direct competitor, the Boeing 787 Dreamliner. The original standard for the A350 provided an internal width of 18 feet and one inch; later versions increased this by four inches through thinner wall construction.

The airline industry often competes on small differences in design. For example, those extra four inches allow some airlines to fit ten seats per row in economy class on an A350—a configuration usually reserved for larger aircraft like those in Boeing’s triple-seven family. While such dense seating increases capacity by around thirty seats on newer A350s, it can reduce individual comfort.

The last Boeing 777-300ER was likely delivered in 2024, with deliveries now limited to freighter variants until certification delays for the new model are resolved. The forthcoming Boeing 777X incorporates several innovations from previous models—including folding wingtips—but its most notable feature is its widened cabin: at 19 feet and seven inches internally, it stands one foot and two inches wider than today’s standard A350.

While both manufacturers have made their cabins four inches wider by reducing wall thicknesses, these changes serve different purposes. For Boeing’s triple-seven line—which has always been configured with ten-abreast seating—the extra space primarily benefits passenger comfort rather than increasing seat count. In contrast, Airbus uses its added space either for additional seats or amenities such as extra trolleys or lavatories due to further interior modifications like shifting bulkheads and cockpit walls.

Despite being physically larger overall than both earlier triple-sevens and rival Airbuses, regulatory limits mean that maximum certified capacities do not always align with size. For instance, although typical configurations see about 426 passengers on a two-class layout aboard a future Boeing 777-9 (with up to ten exit doors supporting evacuation), its official exit limit is estimated at up to 475 passengers—five fewer than what is listed for an Airbus A350-1000 under similar standards.

As development continues on these next-generation widebody jets—with first deliveries of the delayed Boeing model expected no sooner than late this decade—passengers can expect roomier cabins but may find that actual comfort depends heavily on how airlines choose to configure their fleets.