Definition
A leasing arrangement in which one operator provides an aircraft to another operator together with a complete crew, maintenance, and insurance. The lessor retains operational control of the aircraft and is responsible for its airworthiness; the lessee pays for the use of the aircraft and crew, typically on a per-hour or per-block-hour basis.
Plain English
Renting an aircraft that comes with the pilots, mechanics, and insurance already included. The company you rent from still operates the plane; you just pay to use it.
Context Anchor
Seen in airline, charter, and business aviation operations when one operator needs extra aircraft capacity or a temporary replacement aircraft.
Derivation
Called 'wet' because the aircraft arrives ready to fly with everything supplied — by analogy to renting equipment 'wet' (with fuel and operator) versus 'dry' (bare equipment only). The term comes from heavy equipment and marine leasing, where 'wet' meant fuel and crew were included.
Why Pilots Care
A wet lease determines who is legally responsible for flight operations, crew training, and regulatory compliance.
Analogy
It is like hiring a bus with a driver, rather than renting an empty bus and supplying your own driver.
Intuition Check
Do not read wet as meaning the aircraft is wet or used in wet weather. Here, wet means the lease includes operating people and support, not just the aircraft.
Example Sentence 1
When the airline's own fleet was grounded for inspections, it arranged a short-term wet lease to keep its scheduled routes running.
Example Sentence 2
Under the wet lease the lessor provided the crew and remained responsible for the aircraft's airworthiness.