Visit your airline's website to view your reservation. Your reservation will show you how many miles your trip is each way. Log in to your account and click on the link to view your flight. Your flight's mileage is listed under the total length of your flight. Most, but not all airlines provide this information to passengers.
Figure out your flight trip miles by using an online flight mileage calculator. Input your departing airport and your arrival airport. If you have a layover, or multiple layovers, you can enter each of your destinations to figure the exact mileage between each city.
Calculate your trip miles using a mileage calculator on a travel website such as Rand McNally. Enter your starting address and your ending address and click "Calculate" to view the total mileage of your trip.
