When Aircraft Availability Depends on Maintenance Capacity Rather Than New Orders

Airlines can have strong passenger demand.

They can order more aircraft.

They can plan new routes.

And they can still struggle to place enough aircraft into service.

The reason is simple.

An aircraft creates economic capacity only when it is available and airworthy enough to fly.

An aircraft waiting for an engine, a critical part, a maintenance slot, or qualified technicians may exist on the fleet list without contributing to flight capacity.

Aircraft Need an Industrial System Behind Them

Once an aircraft enters service, it depends on much more than the original manufacturing process.

Engines.

Replacement parts.

Inspections.

Repair.

Overhaul.

Tooling.

Maintenance facilities.

Certified personnel.

These functions determine whether a physical aircraft can continue producing flights, seats, cargo capacity, and revenue.

AAR’s MRO Holdings Agreement Shows the Value of Maintenance Capacity

On 28 September, AAR announced an agreement to acquire a 65 percent controlling interest in MRO Holdings.

The equity value of that interest is approximately USD1.8 billion.

AAR described the transaction at an implied enterprise value of approximately USD4.0 billion for MRO Holdings.

Reuters reported that the combined hangar network is expected to service nearly 3,000 aircraft annually.

The transaction remains subject to regulatory and customary closing conditions.

Its scale nevertheless illustrates how valuable maintenance capacity has become while airlines face delayed deliveries and wider aerospace supply-chain constraints.

Sources: AAR; Reuters, 28 September 2026.

Delayed New Aircraft Increase the Importance of Existing Fleets

When new-aircraft deliveries arrive later than planned, airlines cannot renew fleets as quickly as expected.

Existing aircraft may remain in service longer.

Leases may be extended.

Additional aircraft or engines may be leased.

Older fleets can also require more maintenance.

A production delay at the aircraft level can therefore increase maintenance demand elsewhere in the aviation system.

Supply-Chain Constraints Are Already Costing Airlines Billions

IATA estimates that aerospace supply-chain constraints cost airlines more than USD11 billion in 2025.

Approximately USD4.2 billion came from delayed fuel-efficiency savings as airlines operated older aircraft longer.

Another USD3.1 billion came from additional maintenance costs.

Excess engine leasing contributed approximately USD2.6 billion.

Additional spare-parts inventory contributed approximately USD1.4 billion.

These costs demonstrate that constrained aircraft availability affects far more than the maintenance budget.

It influences fleet efficiency, capital use, leasing, and airline operating economics.

Source: International Air Transport Association, 2025-2026.

Engine Maintenance Has Become a Major Constraint

Engine availability provides one of the clearest examples.

IATA reports that the number of grounded Pratt & Whitney GTF-powered aircraft peaked at 648 in March 2025.

That represented approximately 28 percent of the GTF-powered fleet.

The aircraft were waiting for engine shop visits, spare engines, or parts.

The aircraft existed.

But the maintenance and supply system was limiting how much of that fleet could operate.

Source: IATA and Emerton, June 2026.

Engine-Shop Demand Is Expected to Increase Sharply

The maintenance challenge is not expected to disappear simply as current disruption eases.

The installed fleet of latest-generation single-aisle engines is expanding.

IATA and Emerton forecast annual LEAP engine shop visits to rise from approximately 600 to 800 in 2025 to more than 5,000 by 2040.

GTF shop visits are expected to increase from approximately 1,000 to more than 2,000 annually over the same period.

This means maintenance capacity has to expand alongside fleet growth.

Source: IATA and Emerton, Single Aisle Aircraft Engines MRO, June 2026.

A Maintenance Facility Is More Than a Hangar

Expanding MRO capacity requires several elements to work together.

Physical facilities matter.

So do qualified technicians.

Specialized tooling.

Test equipment.

Approved processes.

Spare parts.

Repair capability.

A new building therefore does not automatically create immediately usable maintenance capacity.

Qualified Labour Is a Long-Term Capacity Issue

Aviation maintenance depends heavily on skilled personnel.

In June, IATA cited Boeing’s forecast that the industry will require approximately 710,000 new maintenance technicians over the next 20 years.

Recruitment alone is not sufficient.

Training, practical experience, licensing, retention, and technical competence all take time.

IATA notes that bringing a licensed mechanic from recruitment to full deployment can take years.

Human capacity can therefore limit the usable output of new physical MRO facilities.

Source: International Air Transport Association, World Maintenance and Engineering Symposium, June 2026.

Parts Availability Can Stop a Repair Too

Technicians and workshop space are not enough when a critical part is unavailable.

IATA identifies spare-parts shortages as one of the important causes of current engine MRO disruption.

Repair capacity therefore depends partly on manufacturing capacity elsewhere in the aerospace supply chain.

This also explains why new-aircraft production and maintenance cannot always be considered separately.

Both depend on parts, components, specialized suppliers, and skilled labour.

Keeping Older Aircraft Longer Can Increase Maintenance Demand

Delivery delays encourage airlines to keep older aircraft operating longer.

That preserves flight capacity.

But older fleets may require additional inspections, repairs, component replacement, and maintenance work.

The response to delayed new-aircraft production can therefore increase demand on the maintenance system that is already under pressure.

Maintenance Turnaround Time Has Direct Economic Value

The amount of time an aircraft or engine spends in maintenance affects how quickly it can return to commercial service.

Longer maintenance periods can increase the need for leased engines, leased aircraft, schedule changes, or additional spare capacity.

IATA’s engine MRO study reports cases where turnaround times became substantially longer than normal because of capacity and material constraints.

Maintenance time therefore has an economic consequence beyond the repair itself.

Source: IATA and Emerton, June 2026.

Aftermarket Access Can Affect Effective Maintenance Capacity

IATA argues that greater access to approved aftermarket options can help reduce pressure on aviation maintenance systems.

This can include approved repairs, alternative parts, used serviceable material, and independent MRO providers.

The important qualification is approval.

Aviation maintenance cannot simply substitute an unqualified part or repair process because capacity is constrained.

Safety, technical standards, certification, and regulatory acceptance remain essential.

New Aircraft Eventually Become Maintenance Customers Too

Higher aircraft production remains essential to fleet renewal and aviation growth.

But new aircraft do not remove the long-term need for maintenance capacity.

As larger fleets enter service, they eventually generate additional requirements for inspections, engine work, parts, repairs, and overhaul.

Aircraft production and aircraft serviceability therefore need to expand together.

Passenger Demand Can Remain Strong While Usable Fleet Capacity Is Constrained

Airlines can face a healthy demand environment while struggling to expand supply.

Passengers may want more flights.

Airlines may want additional routes.

But flight growth depends on having enough aircraft available for operation.

Supply-chain constraints have already contributed to higher maintenance, engine-leasing, and inventory costs.

Limited fleet availability can therefore become an economic constraint even when the demand side remains strong.

Maintenance Capacity Is Becoming Strategic Infrastructure

Airports are recognized as aviation infrastructure.

Aircraft are recognized as productive assets.

The maintenance system is also critical to keeping that productive capacity operational.

MRO infrastructure includes not only physical facilities, but people, parts, tooling, repair capability, technical information, and supply networks.

A growing fleet therefore requires a growing maintenance ecosystem.

Resilience Can Require Capacity That Looks Expensive in Normal Conditions

Airlines and maintenance providers also face a familiar operational trade-off.

Spare engines, additional inventory, supplier diversity, and reserve capacity all require capital.

Keeping too much unused capacity can reduce efficiency in normal conditions.

Keeping too little can increase operational disruption when parts, engines, or maintenance capacity become constrained.

Current supply-chain pressure has made that balance increasingly important.

Data and AI Can Improve Maintenance Planning

Better information can increase the effectiveness of existing maintenance capacity.

Airlines can use operational data to improve maintenance forecasting, parts positioning, inventory planning, and repair decisions.

IATA also sees predictive maintenance, digitalization, and artificial intelligence as useful tools for improving maintenance operations.

But digital tools do not eliminate physical constraints.

Software cannot manufacture a missing component.

AI cannot replace an unavailable certified mechanic, engine shop, or test cell.

Digital capability can make physical capacity more effective.

It cannot make every physical bottleneck disappear.

Conclusion

Aviation growth has traditionally been discussed heavily through aircraft orders, manufacturing backlogs, and delivery rates.

Those measures remain important.

But current aerospace supply-chain conditions show that they do not describe the entire capacity problem.

Airlines also need enough engines, parts, maintenance facilities, technicians, repair capability, and aftermarket support to keep aircraft operational.

IATA’s evidence shows how significant those constraints have already become.

Hundreds of GTF-powered aircraft have been grounded while waiting for engine-related maintenance resources.

Maintenance demand for newer single-aisle engines is expected to increase sharply as their installed fleets expand.

Airlines are also paying billions in additional costs associated with delayed fleet renewal, maintenance, engine leasing, and spare inventory.

New-aircraft production therefore remains only one side of aviation capacity.

The other is the industrial system that keeps those aircraft available for service.

As fleets grow, maintenance capacity will increasingly matter alongside manufacturing capacity.

The next important aviation bottleneck may not always be the factory building the aircraft.

It may be the maintenance ecosystem required to keep the fleet flying.