Yield per revenue passenger mile is calculated by dividing passenger revenue by Revenue Passenger Miles.
Yield per revenue passenger mile represents the average amount that a passenger pays to fly one mile. It is usually presented in cents per mile and is useful to assess changes in fares over time. However, yield per revenue passenger miles should not be used to compare performance across markets and/or airlines because it is significantly skewed by flight length and does not account for Load Factor. For example, Southwest and Delta had comparable yields per revenue passenger mile in 2008 but Southwest's Load Factor or 71.2% was significantly lower than Delta's (81.4%), meaning that Southwest was able to breakeven with less seats filled than Delta during the year.
