Aircastle (NYSE:AYR) acquires and leases jet aircraft to airlines, and invests in debt securities that are backed by commercial jet aircraft (in other words, lending money to airlines to buy their own planes). As of February, 2008, Aircastle owned 130 passenger and cargo aircraft, currently valued at $5.7 billion.  90% of Aircastle's aircraft are passenger planes and only 10%  are freighter planes, as Aircastle mainly leases directly to commercial airlines.
Aircastle leases their aircraft on an operating lease basis, which means Aircastle is responsible for maintaining the planes and must recruit and pay for maintenance staff. Aircastle's clients pay a regular monthly fee as part of a long-term lease that usually lasts from 3-12 years. Operating leases are often used by airlines that need greater flexibility in their fleet (whether in type of planes or number of planes) and have capital constraints (thus making it harder for them to acquire and maintain their own fleet). Aircastle's largest clients include U.S. Airways, Sterling Airways and Swiss International Airlines. Revenues are influenced by the supply and demand of aircraft, which is affected by the overall health of the airline industry. This is in turn affected by factors including the general economic outlook, consumers' demand for travel, and fuel prices. 
Aircastle's revenue mainly comes from aircraft leases to airlines. The firm has a very high customer concentration, where their five largest clients are responsible for up to 50% of the revenue. As of December 31, 2007 the company's two largest customers alone, U.S. Airways and Sterling Airways accounted for more than 19% of total revenue. 
From 2005 (when the company was founded) to 2007, the company grew its revenue by an average of 330% annually, and increased its operating income by an average of 509% per year.  As the aircraft leasing industry itself is growing at an average of 6% annually , Aircastle's growth rate is faster than the industry average. This high growth rate is partially because Aircastle was in its development phase as the company was only founded in 2005. This is also a result of the company's ability to acquire second-hand planes at relatively low costs. Aircastle is able to purchase lower-cost planes because instead of buying directly from aircraft manufacturers (which many of their competitors do), they source aircraft through multiple channels across the world, such as sale-leasebacks with airlines, other operating lessors and banks.
The bulk of Aircastle's business comes from outside the U.S., with Europe and Asia accounting for 47% and 27% of total revenue respectively. As North America only accounts for 10% of total revenue, Aircastle is less vulnerable to the volatilities in the U.S. domestic airlines industry. One of the key performance metrics for the airline leasing industry is measured by the operating margin. Aircastle has an operating margin of 56.59% (as of 2007), which is high compared to an industry average of 26.26%.  This is because their operating expenses, excluding the depreciation to their planes, are fairly low.
Post 9/11 concerns for air travel safety and consistent flight cancellations and delays in the U.S. has led to lower consumer confidence and lower demand for flight services. Coupled with the economic slowdown, increasing overhead (as airlines need to allocate bigger budgets to deal with increased security measures) and rising fuel costs has lead to four US airline bankruptcies in April 2008 alone. The main commercial airlines also face decreasing revenues and profit margins due to increased competition from new, low-cost airlines caused by the deregulation of the airline industry. This leads to lower demand for leases from U.S. airlines, which hurts Aircastle's revenues.
The air transportation industry is heavily regulated and any changes in airline regulation will significantly impact Aircastle's clients. The decreasing government protection for state-owned airlines in certain countries in Europe and Asia has led to an increasing amount of privately-owned carriers, many of which are low-cost carriers. This stimulates the demand for aircraft leasing in these markets, as smaller airlines often do not have the capital to buy their own planes and would rather pay a regular monthly fee as part of a long-term lease.
Rising fuel costs, which have increased 74% in the last year alone, lead to decreasing profit margins for most airlines, especially in the US. This is because fuel costs can take up to 30% of an airline's operating expenses. As most airlines' profit margins are already fairly small, rising oil prices can eliminate many airlines' profits. This leads to decreased aircraft leasing demand and lower fees, which has a negative impact on Aircastle's revenue.
Demand for leased aircraft from airlines in emerging markets, such as Asia, continues to grow and has been resilient to the economic slowdown in the US. This stems from the increasing demand for air travel from growing middle classes in emerging markets, including China and India, where the total number of aircrafts is expected to grow by 49% this year.  As Aircastle already has significant exposure in these regions, this trend will lead to more growth for the company.
The total number of aircraft on operating leases worldwide in 2001 was 3,760, representing 24.9% of the world’s fleet. By the end of 2005, this had increased to 5,526 aircraft, representing 30.1% of the world’s fleet . This trend is expected to continue (predicted at least 6% average growth annually) as airlines strive to free up capital for expansion, to maintain a constantly modern fleet of aircraft, and to deal with more fluctuations in travel demand. As demand for air travel changes over time, leases give airlines more flexibility in their fleet and the ability to limit excess capacity. This trend is also due to the increasing number of many private and smaller airlines that do not have the capital to acquire and maintain their own fleet.
Globally, there are more than 260 airlines and 450 leasing companies, carrying a total inventory list of 19,000 airplanes.  The companies compete in the leasing and re-leasing of aircraft, as well as in aircraft acquisition and sales. Thus Aircastle competes with airlines, aircraft manufacturers, other aircraft operating lessors, aircraft brokers and financial institutions. Their main competition includes:
|Net income (USD)||114.1M||(111)M||n/a||499.3M||188.45M|
|# of aircraft (as of 2007)||133||300||1405||866||316|
Aircastle differs from its competitors in that it mainly focuses on seeking out lower-costing used aircraft and does not pursue manufacturers for new orders.
The market share in the aircraft leasing industry calculated below for each company is based on their number of aircraft for lease (in relation to the total number of aircraft on lease globally, which is 5600 as of 2006)