Glossary
Definition: A wet lease is when one airline (the lessor) provides an aircraft, complete crew, maintenance, and insurance (ACMI) to another airline (the lessee) that operates the flight under its own brand. Common for capacity expansion, seasonal demand, or covering aircraft maintenance.
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Term at a glance
| Term | Wet Lease (ACMI) |
|---|---|
| One-liner | A wet lease is when one airline (the lessor) provides an aircraft, complete crew, maintenance, and insurance (ACMI) to another airline (the lessee) that operates the flight under… |
| Where it matters | Premium-cabin booking decisions, fare-rules interpretation, airline-product comparison. |
| Related concepts | Operating Carrier · Marketing Carrier · Codeshare · Wide-Body · IATA |
| Last verified | 2026-05-07 |
When you book a flight on Airline A but board an aircraft painted in Airline B's livery, you're flying a wet-leased flight. The booking carrier (Airline A, the lessee) handles ticketing and customer service; the operating carrier (Airline B, the lessor) provides the metal, pilots, cabin crew, and operational responsibility for safety.
ACMI is the standard wet-lease structure: Aircraft, Crew, Maintenance, Insurance — all four provided by the lessor. The lessee pays a fixed fee per block hour and absorbs fuel, navigation, and airport costs. Common scenarios: - Capacity boost: a carrier needs more wide-bodies during summer peak; wet leases from carriers in their off-season provide flexibility. - Aircraft groundings: when a model gets grounded (737 MAX in 2019; certain Pratt & Whitney engine issues recently), wet leases backfill while the home fleet returns. - Route launches: a carrier launching a new long-haul route may wet-lease aircraft for the first 6-12 months until owned aircraft are delivered.
For passengers, the practical impact: in-flight product (seat, food, IFE) is the operating carrier's, not the booking carrier's. If you booked Lufthansa business class but are flying a wet-leased Hi Fly aircraft, the seat and meal experience will be Hi Fly's — not Lufthansa's. Regulatory protections (EU261, Montreal Convention) are the responsibility of the booking carrier, but service quality is the operator's.
A dry lease (the contrasting structure) is just the aircraft itself — the lessee provides crew, maintenance, and insurance. Most major carriers' fleets include a mix of owned, dry-leased, and wet-leased aircraft.
In booking practice
At a Glance
| Term | Quick definition | Reference |
|---|---|---|
| US Preclearance | A program where US Customs and Border Protection (CBP) operates immigration and customs facilities at foreign… | Read |
| Wide-Body Aircraft | A wide-body aircraft (also called a twin-aisle aircraft) is a large passenger airplane with two passenger… | Read |
| Twin-Aisle | Twin-aisle is another term for wide-body aircraft, referring to the two passenger aisles that run the length… | Read |
| Yield Management | Yield management is the revenue optimisation strategy airlines use to dynamically adjust ticket prices based… | Read |
| Turn-Down Service | Turn-down service in airline business and first class is when cabin crew convert your seat into a bed, laying… | Read |
| TSA PreCheck | TSA PreCheck is a US Transportation Security Administration trusted-traveler program providing expedited… | Read |
Related Terms
A program where US Customs and Border Protection (CBP) operates immigration and customs facilities at foreign airports, allowing passengers to clear US entry before boarding. Available at 15 airports including Dublin, Shannon, Aruba, Bermuda, Bahamas, Abu Dhabi, and several Canadian cities.
A wide-body aircraft (also called a twin-aisle aircraft) is a large passenger airplane with two passenger aisles, typically used for long-haul international flights and capable of carrying 200–850 passengers.
Twin-aisle is another term for wide-body aircraft, referring to the two passenger aisles that run the length of the cabin, allowing wider seating configurations and more spacious premium cabins.
Yield management is the revenue optimisation strategy airlines use to dynamically adjust ticket prices based on demand, booking pace, competition, and time to departure, maximising revenue per flight.
Turn-down service in airline business and first class is when cabin crew convert your seat into a bed, laying out a mattress pad, sheets, duvet, and pillows to create a comfortable sleeping environment.
TSA PreCheck is a US Transportation Security Administration trusted-traveler program providing expedited security screening at over 200 US airports for pre-approved travelers. Members keep shoes, belts, and light jackets on, leave laptops and TSA-compliant liquids in their bags, and use dedicated faster lanes.
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