Airlines that cannot afford to do good business with direct factory aircraft or airlines that wish to maintain flexibility can lease their aircraft using a lease or financing lease. A dry lease is a lease agreement in which an aeronautical finance company (lease), such as GECAS, AerCap or Air Lease Corporation, provides an unmanned aircraft, ground personnel, etc. Dry leasing is generally used by leasing companies and banks, with the taker required to put the aircraft on their own Air Transport Operator (AOC) certificate and allow aircraft to be registered. A typical dry contract lasts up to two years and has certain conditions of depreciation, maintenance, insurance, etc., depending on the geographical location, political circumstances, etc. If all the obligations and responsibilities mentioned in the operating licence are fulfilled, the owner of the leased aircraft becomes an operator. The training and competence of the crew, the maintenance of wet rental aircraft and all other responsibilities are assumed by the owner. The tenant assumes only responsibility for commercial matters that must be expressly admitted to the water lease. In addition, the number of aircraft leased by a given taker must not exceed the number of their fleets. All necessary technical and operational checks must be carried out by the local operator. The water lease is terminated when the standards are covered by the standards set by the Directorate General. In addition, under the Civil Aviation Act, passengers must be informed that the aircraft is subject to wet leasing. In this context, a local aircraft operator who leases the aircraft from another local aircraft operator or an international airline must provide its passengers with information about the de facto operator (i.e. the owner) as soon as possible or at least before boarding.
A ground lease is a lease agreement whereby the lessor (i.e. an airline or aircraft operator) makes available to a taker (i.e. another airline or aircraft operator) with its crew (either a full crew or a single member of the cockpit), maintenance and insurance (both in case of hull and third-party liability). The tenant pays the landlord in proportion to the hours worked. The four main components of a wet leasing are the aircraft, crew, maintenance and insurance. Despite the bankruptcy of Air Berlin and Monarch Airlines, leased aircraft were quickly placed at „normal market rates“ due to traffic growth due to growth in global revenue, as passenger-kilometres increased by 7.7% year-on-year until September 2017 and Airbus is having difficulty supplying A320neos due to delays in the supply of engines.  Ground leases are governed by the Civil Aviation Act and associated legislation and are ideal and convenient for start-up airlines, for exploring new routes or seasonal fluctuations and sudden peaks in demand. In addition, wet leases are likely to also meet the needs of long-term fleet development plans and maximize market share in the immediate future. Wet leasing is sometimes used for political reasons. For example, EgyptAir, an Egyptian government company, cannot fly to Israel under its own name because of a well-founded Egyptian government policy. As a result, Egyptian flights from Cairo to Tel Aviv are operated by Air Sinai, which is leased by EgyptAir wet to bypass the political issue.  Jet leasing accounted for less than 2% of the fleet in 1976, then 15% in the early 1990s, 25% in 2000 and 40% in 2017, with owners participating in 62% of quarantine aircraft transactions in the second half of the year since 2000: 42% in Europe and 29% in North America.
 In 2015, more than $120 billion worth of commercial aircraft were delivered worldwide, and half of the world`s owners were based in Ireland.  As part of the Civil Aviation Act