Airfares are low when demand is low, typically far in advance of departure. Conversely, airfares can be cheapest at the last minute, sometimes as soon as a day in advance of travel. The fare history charts on Kayak.com display airfares by day of purchase and demonstrate how prices rise closer to date of travel.
The day of the week you make your reservation also affects the cost of your ticket. Airlines post fare sales and last minute deals in the beginning of the week. For example, JetBlue posts deals on Twitter as "JetBlueCheeps" on Tuesdays for last-minute travel.
Airlines charge ticket cancellation fees. Ticket cancellation insurance -- sold by most airlines, travel agencies, and ticket search engines -- is a one-time fee that protects you from paying extra if you cancel. Ticket cancellation insurance is advisable if you buy your ticket well in advance of travel.
Some airline sales may only be available to customers in their home country. Consider buying international flights between international destinations once you are already abroad.
