The Jets Are Flying Again, But Engine Costs Keep Climbing

Global air travel has largely recovered and jets are back in the sky, but airlines are still wrestling with an uncomfortable legacy of the pandemic and the latest generation of engines: maintenance and overhaul bills that continue to climb even as traffic and profits rebound.

Traffic Recovers Faster Than the Engine Supply Chain

Industry forecasts show global passenger traffic either back to or slightly above pre‑pandemic levels, with many carriers reporting record load factors and restored capacity on key routes. Publicly available schedules data and airline financial updates indicate that narrowbody workhorses such as the Airbus A320neo family and Boeing 737 MAX are flying more hours and cycles than ever, reflecting strong demand for short and medium haul travel.

Behind the scenes, however, the supply chain that supports their advanced turbofan engines has struggled to keep pace. Published coverage in aviation trade outlets describes a tight market for critical hot‑section parts, casting materials and repair capacity, particularly for the CFM International LEAP and Pratt & Whitney geared turbofan families. Engine makers have ramped production and expanded maintenance, repair and overhaul networks, but lead times for shop visits and spare engines remain elevated compared with historical norms.

This imbalance between rising utilization and constrained maintenance capacity is feeding directly into airline cost bases. Carriers that had expected new‑technology engines to deliver lower total ownership costs are instead facing extended turnaround times, higher material prices and more frequent early removals than originally planned. Even as revenue recovers, these unexpected burdens are showing up in increased maintenance expense per flight hour.

Durability Growing Pains for New‑Generation Engines

The latest narrowbody engines were launched with ambitious promises on fuel burn and emissions, and in service they have generally delivered significant efficiency gains over older CFM56 and V2500 models. At the same time, a series of durability issues has emerged as fleets have built up hours in hot, dusty and high‑cycle environments. Public engineering updates from CFM highlight the introduction of high‑pressure turbine durability kits and reverse bleed systems for LEAP‑1A engines, specifically intended to extend time on wing and reduce on‑wing fuel nozzle replacements.

Analyst appraisals of the LEAP‑1B for the 737 MAX point to a succession of retrofit campaigns addressing components such as radial drive shaft bearings, turbine shrouds and vibration‑related hardware. While such modifications are a normal part of maturing a new design, they require engines to visit the shop earlier or more often than first projected, translating into extra cost and downtime for operators.

The Pratt & Whitney geared turbofan family has faced a separate set of challenges. Company statements and regulatory filings detail an extensive inspection and removal program linked to a rare condition in powdered metal used for certain parts of PW1100G‑JM engines. The resulting wave of accelerated shop visits has grounded hundreds of aircraft at various points and forced airlines to lease capacity, adjust schedules or swap aircraft types, all of which carry direct and indirect costs.

For airlines, the net effect is that headline gains in fuel efficiency are being offset by maintenance bills that are higher and arrive sooner than initially forecast. Over time, durability upgrades are expected to stabilize the picture, but for now many carriers are navigating an expensive transition period.

Shop Bottlenecks and Parts Inflation Squeeze Airlines

Engine maintenance shops are reporting heavy backlogs as they work through both scheduled overhauls and unplanned removals. Industry data presented at recent maintenance conferences show a rise in unscheduled shop visits for newer engine types, as well as longer turnaround times driven by parts shortages and labor constraints. Airlines that once budgeted for a set number of days for an overhaul are now increasingly planning for engines to be out of service for significantly longer.

The surge in demand for overhauls has coincided with inflation in specialized materials and components, from turbine blades to fuel system parts. Financial reports from major engine manufacturers indicate higher aftermarket revenues, reflecting both volume and pricing effects, even as they invest in expanding repair capacity and redesigning parts to improve durability. For operators, this translates into larger invoices per shop visit and more pressure on cash flow.

Leasing markets add another layer of cost. With shop slots tight, airlines are relying more on spare engine leases to keep fleets flying. Lessors and engine pool providers are in a stronger negotiating position, and rates for new‑technology powerplants have risen accordingly. When combined with the lost revenue from aircraft that remain on the ground awaiting engines, the total economic impact of these bottlenecks far exceeds the line item labelled maintenance in many income statements.

Strategic Shifts in Fleet and Engine Choices

Persistent engine issues and rising lifecycle costs are starting to influence strategic decisions on fleet planning. Some airlines have publicly disclosed adjustments to delivery schedules, engine selection on new aircraft orders, or lease extensions for older but proven fleets. Industry commentary notes that several carriers have diversified their narrowbody engine choices, opting for mixed LEAP and geared turbofan fleets to hedge operational and financial risk.

In regions where groundings linked to specific engine types have been most acute, capacity constraints have reshaped competitive dynamics. Low‑cost carriers that depend heavily on high utilization of a single narrowbody type have been particularly exposed. Financial disclosures from affected airlines reference negotiations with manufacturers for financial compensation, but those arrangements typically offset only part of the revenue loss and do not erase higher operating costs.

At the same time, there is renewed appreciation for the mature economics of previous‑generation engines. While less efficient in fuel burn, CFM56 and V2500 fleets benefit from well‑understood maintenance profiles, abundant parts in the secondary market and a broad network of independent repair providers. Some operators are extending the lives of older jets or acquiring used aircraft to bridge the gap while new‑engine reliability and cost curves stabilize.

Longer Term: When Do the Bills Come Down?

Engine makers are signaling that the worst of the disruption may be finite. Public roadmaps from both CFM and Pratt & Whitney outline hardware upgrades, redesigned components and expanded overhaul capacity intended to reduce early removals and cut turnaround times over the next several years. Predictive maintenance tools and enhanced health monitoring are being deployed to catch emerging problems earlier and manage fleets more efficiently.

Analyst forecasts suggest that as these technical fixes take hold and the backlog of powder‑metal inspections and retrofits is cleared, unscheduled shop visits should decline and time on wing should gradually approach original design targets. That, in theory, would allow airlines to capture more of the promised fuel and emissions benefits without surrendering those gains to unexpected maintenance spending.

For now, though, the reality is that the jets are flying again, but the balance of costs has shifted. Engine OEMs are booking strong aftermarket revenues, lessors are enjoying robust demand for spares, and MRO providers are running close to capacity. Airlines, even amid healthy passenger demand, are learning that the transition to more efficient propulsion technology comes with a multi‑year bill that is only now coming fully into view.