Although airlines differ in how they determine fares, there are several common variables that many of them use. These variables include competition on the route (determined by how many other carriers offer flights to a destination), seat demand, distance of the route, seat supply and fuel prices, which can fluctuate from one week to the next. Airlines often establish separate price points for economy class and business class, as well as for domestic and international flights.
Buying your tickets well in advance of your travel date is the first step in getting a cheaper ticket. Because the number of cheap fares is limited, these seats tend to sell quickly and the chances of grabbing one increases if you buy weeks or months ahead of time. In addition, prospective ticket buyers should always ask the airline reservations agent for the lowest available fare and how to meet its requirements, according to the U.S. Department of Transportation's Aviation Consumer Protection and Enforcement division.
For many airlines, the cheapest tickets are for travel on Tuesday, Wednesday and Thursday departures. The rationale for this is simple: These are midweek days that don't involve travelers going home for the weekend or returning from weekend trips. According to Fare Compare, Wednesday is the cheapest of the three days because more seats are available in the exact middle of the week when business travelers are not flying; supply exceeds demand, forcing airlines to make those fares lower than normal.
Although airline tickets are cheapest in the middle of the week, carriers may still attach restrictions to these fares. These restrictions may include a minimum stay, return requirements that limit you to coming back from your destination in the middle of the week, flight times in the early morning or late evening, maximum stay restrictions of 30 days or less, blackouts that prohibit cheap fares during "high" seasons (such as summer and holidays) and restrictions on non-stop routes.
