Shopping for airline tickets has come a long way since the days of calling the airline companies directly to reserve your itinerary. The advent of the internet has given everyday consumers the ability to book airfares without the assistance of airline customer service representatives or travel agents. Here’s some information that will make you more knowledgeable about how to get the best deal when booking flights yourself online.

Have you ever seen the prices for a flight fluctuate drastically in the same day? This is because most airlines use robust, database driven software that factors historical purchase data along with current ticket supply and demand to determine ticket prices. For example, if a flight is selling out too fast compared with past flights for that same route, ticket prices will rise and vice versa. Prices are updated multiple times a day and even real-time in some systems.

Are you a business traveler? Airline companies are well aware that businesses are willing to pay more for airfares then the average consumer, so they commonly implement the “Saturday Night Stay Over” requirement to capitalize on them. If you’re a non-business traveler try to incorporate a Saturday night stay over to avoid this fee. If you’re on business, show your employer how much they’ll save by letting you stay the weekend, if you so desire.

What are the most inexpensive days to fly? Tuesdays and Thursdays are historically the cheapest days to fly, with Wednesdays and Saturdays being a close second. Fridays and Sundays are the most expensive. This all goes back to the aforementioned ticket demand data that helps determine ticket prices. The same holds true for seasonal popularity and “times of day”. Flying red-eye during non-peak seasons is generally cheaper because those flights have less demand.

When is the best time to book my flight? Prices on last minute airfare can be highly volatile so try to book in advance. At the last minute, airlines know you’re desperate and are willing to pay more. However, occasionally the airlines are desperate to fill seats, so prices might decrease. For travel during popular holidays (i.e. Christmas, New Years, Thanksgiving) and internationally try book at least three months in advance. Most travel sites recommend booking 7, 14 or 21 days in advance, but in my experiences the rates associated with these intervals usually get bought up way before then. So, even for domestic flights I start looking several months in advance.

One of the most important things to consider when traveling is to try to resist mainstream travel patterns. If you can avoid traveling during peak seasons, “days of the week” and “times of the day” you can experience substantial savings. If you can think “outside the box” when planning your trip, you can find the discount airfares the airlines were forced to mark down to ensure a sold-out flight.