Passenger demand fell 2.2 percent in May while air cargo rose 6.0 percent. The divergence is clear enough. What is less visible, and more structural is the engine maintenance bottleneck that IATA has now labelled an industry emergency.
In a study released in late June with consultancy Emerton the association examined the maintenance, repair and overhaul of the two engines that power the bulk of the modern single-aisle fleet. The CFM LEAP and the Pratt & Whitney Geared Turbofan. Durability shortfalls, scarce spare parts, limited spare engines and restricted aftermarket access have reduced time-on-wing, accelerated shop visits and complicated fleet planning. Grounded GTF-powered aircraft peaked at 648 in March 2025, equal to 28 percent of that fleet. Airlines responded by retaining older aircraft extending leases and leasing additional capacity at elevated rates.
The forward numbers are steeper. Annual LEAP shop visits are projected to climb from roughly 600–800 in 2025 to more than 5,000 by 2040. GTF visits are expected to rise from about 1,000 to more than 2,000 over the same period. Manufacturers are adding capacity yet IATA’s director general, Willie Walsh, has stated that capacity alone will not solve the problem. Airlines need faster approval of repair solutions, expanded production of critical components, fairer access to shop slots and greater competition in the aftermarket.
Exposure is uneven. Carriers with large concentrations of A320neo or 737 MAX aircraft powered by the affected engines face the sharpest constraints. IndiGo one of the largest A320neo operators, has retained older A320s, extended leases on dozens of aircraft and arranged additional short-term capacity. European low-cost operators that built growth plans around high utilisation of neo and MAX fleets have likewise been forced to keep older frames flying longer. Network carriers with mixed fleets can absorb some of the pressure by shifting flying but pure single-aisle operators cannot.
The bottleneck compounds an already difficult cost environment. Jet fuel remains far above pre-crisis levels even after recent declines. Older aircraft burn more fuel. Higher maintenance costs and elevated lease rates for replacement capacity further compress margins. IATA has already revised industry profitability sharply lower for 2026 citing Middle East disruptions and fuel prices. Engine-related groundings and extended shop times add a second, less negotiable layer of expense that cannot be passed through fully in competitive markets.
Cargo’s resilience offers limited relief. Belly capacity on passenger aircraft is reduced when those aircraft are parked awaiting engines. Freighter operators face their own maintenance queues. The net result is an industry that is simultaneously short of modern, efficient aircraft and short of the shop capacity required to keep the existing fleet flying. Until spare-parts flow, repair approvals and aftermarket access improve, the engine bottleneck will continue to shape schedules, costs and fleet plans more tightly than headline demand figures alone suggest.