The Plane Is Fine. It Just Needs an Engine.

An Airbus A320neo is sitting at the airport.

There is nothing wrong with the wings. The cabin is fine. The landing gear works.

But the aircraft is not flying.

One of its engines has been removed for maintenance, and there is no replacement ready to take its place.

This is not an unusual problem in commercial aviation. In March 2025, 648 aircraft powered by Pratt & Whitney's GTF engines were grounded while waiting for engine shop visits, spare engines or parts, according to the International Air Transport Association. That was 28% of the GTF-powered fleet at the time.

Some reported engine shop visits have taken as long as 300 days.

Parking an airliner for months because of one missing engine sounds absurd until you look at what that engine is worth.

Nearly Half the Value of the Plane Can Be in Its Engines

Most passengers probably think of a jet engine as one very expensive component of an airplane.

On some new aircraft, that understates it.

Aircraft valuation firm mba Aviation calculated that two new-generation engines represented about 45% of the market value of a new narrowbody aircraft in early 2024.

The numbers vary by engine.

On a new A320neo powered by two Pratt & Whitney PW1127G engines, the engines represented 50.5% of the aircraft's market value. With two CFM LEAP-1A26 engines, the figure was 42.9%.

Two LEAP-1B27 engines on a new Boeing 737 MAX 8 represented about 42%.

A generation earlier, engines typically accounted for roughly 25% to 30% of the value of a new A320ceo or 737NG.

That changes the way an airplane looks as an asset.

What appears to be one machine worth tens of millions of dollars is really a collection of extremely valuable components. The two objects hanging under the wings can account for close to half of the whole thing.

So Is the Engine Included in the Price of an Airplane?

Usually, when someone talks about the market value of a complete operating aircraft, the engines are part of that value.

But aviation does not treat an engine the way a car owner normally treats a car engine.

A commercial jet engine has its own serial number and maintenance history. Its operating hours and cycles are tracked. So are the lives of critical parts and the work performed during previous shop visits.

Two engines of exactly the same model can therefore have very different values.

An engine fresh from major maintenance is not economically identical to one approaching an expensive shop visit.

More importantly, the engine does not have to remain with the same aircraft forever.

It can come off.

Another compatible engine can go on.

That simple fact supports an entire business.

What Happens When an Engine Comes Off?

Go back to the A320neo sitting at the airport.

Suppose one engine needs major maintenance.

The airline removes it and sends it to an engine shop. The aircraft itself remains behind.

Waiting would be the simplest option. Eventually, the engine comes back and the airline puts it back on the aircraft.

The problem is the waiting.

An aircraft sitting on the ground is not selling seats. If it is leased, payments may still be due. Other ownership and operating costs do not simply disappear because the aircraft cannot fly.

And right now, waiting for engines can take a long time.

IATA says shortages of parts and spare engines, durability problems and limited maintenance capacity have created a major bottleneck for the newest generation of single-aisle engines.

For airlines, there is another option.

They can rent an engine.

Yes, Airlines Can Rent Just the Engine

This is the spare-engine leasing business.

The airline's original engine goes to the shop.

A compatible engine owned by a lessor is installed on the aircraft.

The aircraft goes back into service.

When the original engine eventually returns, the airline can remove the leased engine and send it back.

That engine may later end up under the wing of another airline's aircraft.

From a passenger's perspective, almost nothing has changed.

From a financial perspective, a multimillion-dollar asset has moved from one aircraft to another and generated lease income along the way.

This is why an aircraft engine is more than a component.

It can behave like a standalone asset.

Why Not Just Buy Another Engine?

Because spare engines are expensive, and airlines do not necessarily need them permanently.

An airline might need an additional engine only while another one is being inspected or rebuilt. Buying a scarce, high-value engine for a temporary problem can tie up a large amount of capital.

Leasing converts that problem into a temporary expense.

And demand for those temporary engines has become expensive enough to show up in the finances of the entire airline industry.

IATA and Oliver Wyman estimated that aerospace supply-chain problems cost airlines more than $11 billion in 2025.

Of that total, approximately $2.6 billion came from increased engine-leasing costs as engines spent longer in maintenance.

Another $3.1 billion came from higher maintenance costs.

The shortage of engines is no longer simply a maintenance issue. It has become a capital problem.

An Engine Can Age Differently From the Airplane Around It

There is another unusual feature of aircraft economics.

As an airplane gets older, its airframe generally loses value.

An engine can follow a different path.

A serviceable engine can be removed and used elsewhere. Its value depends heavily on its maintenance condition, remaining useful life and demand for that particular engine type.

This can produce situations that seem backwards.

mba Aviation estimated that for a five-year-old new-generation narrowbody aircraft, the value of its two engines at half-life condition could represent about 61% of the aircraft's total value.

Current supply shortages have pushed the relationship even further in some valuation scenarios. IATA has noted that the market value of two full-life engines can now approach 80% of the value of a new aircraft.

Eventually, the economics of an aging airplane can become strange enough that its components are worth more separately than the aircraft is worth staying together.

At that point, an owner has a different question to answer:

Is this airplane worth keeping in service?

Or is it worth more as engines, landing gear and other parts?

Retiring an aircraft does not necessarily mean retiring its engines.

Who Actually Owns the Engine Under Your Wing?

There is no single answer.

An airline may own its aircraft and engines.

It may lease an aircraft with engines attached.

It may temporarily lease a spare engine while one of its own engines is being repaired.

Aircraft lessors, specialist engine lessors, maintenance companies and other owners can all participate in this market.

Which means the engine carrying you across the Atlantic today does not necessarily have to belong to the airline whose name is painted on the airplane.

It may not even remain on that airplane.

Eventually it could be removed, serviced, leased again and installed under the wing of another aircraft operated by another airline.

Passengers see one airplane.

The aviation industry sees something more complicated: an airframe, engines, landing gear, avionics and other high-value assets, each with its own maintenance needs, useful life and economics.

And right now, one of the most valuable and difficult assets to replace is hanging under the wing.

Sometimes the airplane really is fine.

It just needs an engine.

BEYOND THE OBVIOUS.

Sources

IATA — Urgent Action Needed to Ease Engine MRO Bottlenecks

IATA — Optimizing Decisions Amid Aviation Supply Chain Turmoil

mba Aviation — Narrowbody Engine Values as a Proportion of Aircraft Values