Airlines may need additional aircraft for a few weeks, an entire season or several years. Choosing the right leasing structure depends on how quickly the capacity is required, who will operate the aircraft and which party will provide the crew, maintenance and insurance.
The main choice is usually wet lease vs dry lease, but ACMI, damp lease, operating lease and finance lease arrangements may also be considered. Each structure allocates responsibilities differently between the aircraft owner or lessor and the airline or lessee.
What is the difference between a wet lease and a dry lease?
The essential difference is operational responsibility.
With a wet lease, the lessor supplies the aircraft together with essential operational services. With a dry lease, the lessor supplies the aircraft only, while the lessee provides the crew and assumes responsibility for operating it.
A wet lease can provide relatively rapid access to operational capacity. A dry lease generally requires more preparation but gives the lessee greater control over the aircraft and its operation.
What is a wet lease or ACMI lease?
A wet lease is an aircraft leasing arrangement in which the lessor normally provides:
- Aircraft
- Crew
- Maintenance
- Insurance
These four elements form the abbreviation ACMI, which is why “ACMI lease” and “wet lease” are frequently used interchangeably in commercial aviation.
The aircraft is normally operated under the lessor’s Air Operator Certificate and operational control, subject to the applicable regulatory approvals and the terms of the agreement. The lessee controls the commercial programme and commonly remains responsible for costs such as fuel, airport charges, navigation fees and ground handling, although the precise allocation must be defined in the contract.
A wet lease can be suitable for seasonal demand, new route launches, aircraft-on-ground disruption, delayed aircraft deliveries and other temporary capacity requirements.
Learn more about what an ACMI lease includes, including aircraft, crew, maintenance and insurance.
What is a dry lease?
Under a dry lease, the lessor provides the aircraft without crew, maintenance or operational support. The lessee places the aircraft on its own Air Operator Certificate and is normally responsible for:
- Flight and cabin crew
- Training and crew planning
- Maintenance and continuing airworthiness
- Aircraft insurance
- Operational control
- Regulatory compliance
- Fuel, handling and airport-related costs
A dry lease is often more appropriate for an established operator that already has the required infrastructure, approvals and personnel. It can provide greater operational control and may suit medium- or long-term fleet planning.
However, introducing a dry-leased aircraft can take longer than arranging an ACMI operation. The operator may need to complete technical inspections, aircraft registration, crew training, maintenance planning and regulatory approvals before commercial service begins.
Explore our dry lease aircraft solutions if your airline has the operational capability to manage the aircraft directly.
What is a damp lease?
A damp lease sits between a wet lease and a dry lease. The lessor provides the aircraft and some operational services, while the lessee supplies other elements.
For example, the lessor may provide the aircraft, flight-deck crew, maintenance and insurance while the lessee supplies its own cabin crew. The exact allocation varies between agreements and regulatory jurisdictions, so every responsibility should be clearly recorded in the contract.
A damp lease may be considered when the lessee wants to use its own cabin service and customer-facing personnel but still needs the lessor to operate and maintain the aircraft.
Wet lease vs dry lease: responsibilities at a glance
| Responsibility | Wet lease/ACMI | Dry lease | Damp lease |
|---|---|---|---|
| Aircraft | Lessor | Lessor | Lessor |
| Flight crew | Lessor | Lessee | Usually lessor |
| Cabin crew | Usually lessor | Lessee | Often lessee |
| Maintenance | Lessor | Lessee | Usually lessor |
| Insurance | Lessor | Lessee | Defined by agreement |
| Operational control/AOC | Normally lessor | Lessee | Normally lessor |
| Typical duration | Short or medium term | Medium or long term | Flexible |
| Typical purpose | Rapid additional capacity | Fleet expansion | Shared operational solution |
The exact contractual and regulatory responsibilities can vary. Operators should therefore assess the complete agreement rather than relying only on the name assigned to the lease.
When does a wet lease make sense?
A wet lease may be preferable when an airline:
- Needs capacity at relatively short notice
- Must cover an aircraft-on-ground event
- Is responding to seasonal passenger demand
- Wants to test or launch a new route
- Is waiting for aircraft deliveries or maintenance completion
- Does not have sufficient crews for additional aircraft
- Requires an aircraft type not currently on its Air Operator Certificate
Because the aircraft arrives with an operating framework, a wet lease can reduce the preparation needed before services begin. Availability and regulatory approval still determine the actual start date.
When does a dry lease make sense?
A dry lease may be more suitable when an airline:
- Requires aircraft for a longer period
- Has its own qualified crews
- Can manage maintenance and continuing airworthiness
- Wants direct operational control
- Has the necessary regulatory approvals
- Intends to integrate the aircraft into its existing fleet
The headline rental cost should not be considered in isolation. Crew, maintenance, insurance, transition, training and return-condition obligations can materially affect the total cost of a dry lease.
Operating leases and finance leases
Wet, dry and damp leases describe the allocation of operational responsibilities. Aircraft leases can also be classified according to their financial structure.
An operating lease provides use of an aircraft for an agreed period without transferring ownership. The aircraft is normally returned to the lessor when the lease ends, subject to the agreed return conditions.
A finance lease is structured more like long-term financing. The lessee assumes a greater proportion of the economic risks and responsibilities connected with the aircraft, and the arrangement may include a purchase option or ownership transfer.
Accounting, tax and legal treatment depends on the agreement and the relevant jurisdiction.
Choosing the appropriate aircraft lease
Before approaching the market, an operator should define:
- Required aircraft type and configuration
- Passenger or cargo operation
- Intended routes and operating regions
- Required start date
- Expected lease duration
- Minimum guaranteed utilisation or block hours
- Crew requirements
- Maintenance responsibilities
- Required regulatory approvals
- Preferred commercial structure
Clear requirements make it easier to identify suitable aircraft and compare realistic proposals.
Discuss your aircraft leasing requirement
ACMI Lease helps airlines and operators identify aircraft capacity aligned with their operational requirements. Whether you need an ACMI, wet lease, damp lease or dry lease solution, provide as much information as possible about the aircraft, start date, duration, routes and expected utilisation.
Send us your aircraft requirement to discuss current options.
Frequently asked questions
Is an ACMI lease the same as a wet lease?
An ACMI agreement is the most common form of wet lease in commercial aviation. The lessor provides the aircraft, crew, maintenance and insurance, although individual contractual terms can vary.
Does a dry lease include pilots or cabin crew?
No. A dry lease normally provides the aircraft only. The lessee supplies the crews and takes responsibility for operating and maintaining the aircraft.
Can a wet lease be used for short-term capacity?
Yes. Wet leases are commonly used for temporary or seasonal capacity, disruption cover and route launches. Longer arrangements are also possible depending on aircraft availability and regulatory approval.
Who operates the aircraft under a wet lease?
The lessor normally operates the aircraft under its own Air Operator Certificate and operational control. The lessee markets the service and determines the commercial programme, subject to the agreement and applicable regulations.