DEFINITION of 'Cost Per Available Seat Mile  CASM'
A common unit of measurement used to compare the efficiency of various airlines. It is obtained by dividing the operating costs of an airline by available seat miles (ASM). Generally, the lower the CASM, the more profitable and efficient the airline.
INVESTOPEDIA EXPLAINS 'Cost Per Available Seat Mile  CASM'
CASM is usually a more comprehensive measurement of airline costs, but it's still important that investors are aware of what items comprise this measurement. Many carriers exclude fuel costs from operating expenses, making the CASM an unreliable metric. Cost per available seat mile, as the name suggests, reflects the costs incurred by an airline to fly a single seat one mile.
RELATED TERMS

Robert Crandall
A former president, CEO and chairman of AMR Corporation, the ... 
Revenue Passenger Mile  RPM
A transportation industry metric that shows the number of miles ... 
Economics
A social science that studies how individuals, governments, firms ... 
Dow Jones Transportation Average ...
A priceweighted average of 20 transportation stocks traded in ... 
Soft Metrics
A slang term for intangible indicators used to value a startup ... 
Econometrics
The application of statistical and mathematical theories to economics ...
Related Articles

Fundamental Analysis
What is the difference between profitability and profit?
Calculating company profit and profitability are not one and the same, and investors should understand the difference between the two terms. 
Fundamental Analysis
How do you calculate rsquared in Excel?
Calculate Rsquared in Microsoft Excel by creating two data ranges to correlate. Use the Correlate formula to correlate both sets of data, or x and y. 
Personal Finance
Where To Get The Cheapest Airline Tickets
We test out a range of ways to get cheap tickets for your next flight. 
Investing
What Happened To Obama’s Amnesty Bill?
The sweeping Republican majorities were supposed to trigger change, but now they are preparing to embrace the Obama immigration policy. 
Fundamental Analysis
What are the most common issues with Serial Correlation in stocks?
Read about the concept of serial correlation in stock returns, and learn why market analysts are divided about the efficacy of trading based on stock patterns. 
Fundamental Analysis
What is the difference between the acid test ratio and working capital ratio?
Using liquidity ratios to determine the financial stability of a company is an important tool to accounting professionals and investors. 
Fundamental Analysis
Do you always have to consider intrinsic value when purchasing a stock? Why or why not?
Take a deeper look at why value investors consider a stock's intrinsic value an important consideration before picking a company to invest in. 
Fundamental Analysis
What are some examples of return on investment capital?
Read about some basic examples of return on investment capital for publicly traded companies and companies that have a handful of investors. 
Bonds & Fixed Income
What is the difference between the yield of stock and the yield of a bond?
Explore and understand the various meanings of the investment term "yield" as it is applied to equity investments and bond investments. 
Fundamental Analysis
For which types of investments is the debt service coverage ratio (DSCR) the most useful?
Understand what the debt service coverage ratio is used for and what types of companies it can best be applied to for equity valuation.