Frequent flyer miles can be your ticket to free flights, cabin upgrades or elite status, which can provide you with big perks, such as priority check-in, boarding, baggage and lounge access.
But all air tickets are not the same. Each one has its own fare class that dictates how many air miles you earn. In most cases, the more money you pay for a ticket, the higher the fare class you book. However, sometimes the difference between a high-earning ticket and one that gives no miles at all is a matter of just a few dollars.
