17,000 Aircraft on Backlog: Aviation’s Supply Chain Crisis

Key Takeaways: 

• Engine supply constraints are forcing airlines to extend fleet lifecycles and push global MRO spending toward $193 billion by 2036, according to Oliver Wyman’s 2026-2036 forecast.
• Aircraft backlogs exceed 17,000 units as casting and forging delays sideline more than 3,500 engines awaiting critical components, costing the industry more than $11 billion in 2025 alone.
• Aftermarket solutions, including Used Serviceable Material and Parts Manufacturer Approval, are becoming popular as operators decrease dependency on OEM supply chains.

Head to the airport today, and it would be hard to tell there’s a shortage of anything other than air traffic controllers. However, internationally the supply chain is tightening.

Aircraft sit without engines. Overhaul queues stretch for months. The global backlog of commercial aircraft has topped 17,000 units, the equivalent of roughly 12 years of current production, and the binding constraint isn’t airframes. It’s engines.

The Engine Shortage That Grounded Expectations

Engine supply, not airframe delivery, is the industry’s primary choke point. According to Cassel Salpeter & Co analysis, more than 3,500 commercial engines are stalled globally, awaiting critical castings and forgings. Overhaul turnaround times have roughly tripled since pre-pandemic norms, climbing from 60 to 90 days in 2019 to between 180 and 240 days in 2026. The Pratt and Whitney GTF powder metal inspection campaign significantly accelerated the backlog, pulling hundreds of Airbus A320neo aircraft off the line simultaneously. CFM LEAP engines face their own pressure as shop visits accumulate. The result is completed aircraft parked without engines while airlines absorb costs on both ends.

Why Castings and Forgings Matter More Than You Think

The bottleneck runs deep into the supply chain, down to the forge shops and foundries that produce turbine disks, shafts, and structural assemblies. These components require aerospace-grade titanium and nickel-based superalloys from qualified, certified sources. Geopolitical disruptions, including sanctions tied to the Russia-Ukraine conflict and pressure on critical materials access, have lengthened lead times well above pre-pandemic baselines. Items that once carried four- to six-week lead times now routinely quote 20 to 40 weeks, per Safe Fly Aviation’s 2026 industry analysis.

The constraint rarely lives at a single stage. Raw material procurement, heat treatment, machining, non-destructive testing, and certification review stack on top of one another. Even one specialized fastener shortage can halt final assembly. That’s the delicacy operators are managing every day.

The $11 Billion Cost of Waiting

IATA has put a number on all of these issues: supply chain problems cost the airline industry more than $11 billion in 2025. Delayed fuel savings from older aircraft still in service account for $4.2 billion. Heightened maintenance costs on aging fleets add $3.1 billion. Excess engine leasing runs to $2.6 billion. Extra spares inventory stockpiling contributes another $1.4 billion. This hasn’t let up this year either. IATA and Oliver Wyman both note that these costs carry directly into 2026 planning assumptions, with no material relief expected in the near term.

How Airlines Are Fighting Back

Operators aren’t waiting for supply chains to normalize on their own. The most effective responses share a common logic: buy certainty where you can’t buy parts. That means signing long-term MRO agreements now to lock in slot priority and cost predictability. It means raising spare engine inventories and favoring engines with larger aftermarket support. It means building relationships with trusted used serviceable material and parts manufacturer approval suppliers and upholding strict traceability to meet government regulations. Engine leasing functions as a flexible bridge instead of a permanent fix, giving carriers coverage while overhaul queues clear.

When OEM timelines slip, operators look elsewhere, and the aftermarket is absorbing that demand. According to IATA’s own survey data, 74% of participating airlines now use parts manufacturer approval parts to manage the supply chain. Designated engineering representative repairs are also rising, letting operators extend component life without full OEM dependency. The global engine parts manufacturer approval and designated engineering representative repair market was valued at $5.6 billion in 2024 and is projected to grow at a compound annual growth rate of 5.8%, per Strategic Market Research. Regulatory bodies and IATA are actively working to clear the path, including renewed agreements with CFM that formally recognize alternative parts and independent repairs under warranty.

What Comes Next

IATA is pressing four strategic priorities: expanding materials capacity, opening the MRO aftermarket to fair competition, improving supply chain data visibility, and developing cleaner traceability standards. Progress has been gradual. Oliver Wyman’s 2026-2036 Global Fleet and MRO Market Forecast projects MRO spending climbing from $136 billion in 2025 to $193 billion by 2036. Engine maintenance will take the largest share of that growth.

Structural hurdles, including casting and forging lead times, certified engineer shortages, and raw materials geopolitics, aren’t resolving quickly. Carriers and suppliers that build diversified sourcing strategies, strong aftermarket relationships, and longer planning horizons will be better placed when the cycle turns.