In these days of ever escalating prices, is it still possible to find cheap airfares online? The answer is a definite yes but you first have to understand the booking process and how airlines sell their tickets.

Most online airline tickets purchased in the USA and Europe are booked using one of four major GDS (Global Distribution Systems) booking engines: Amadeus, Sabre, Galileo, and Worldspan. These are operated by the major world airlines.

Travel agents and online travel booking sites use them almost exclusively to obtain their tickets.

If everyone is using basically the same sources to obtain discount airfare tickets you would expect prices to be very similar across the board. But in fact, there are major differences in pricing for flights on the same routes from site to site. Why should this be?

In my opinion there are two main reasons for variations in the pricing of cheap airfares. They are:

  1. Booking fees

  2. Consolidator fares

Booking fees were introduced when the airlines ceased paying commissions to travel agents and discount airfare websites for reselling their tickets. The only way left to make a profit was to charge an additional booking fee for each ticket sold. These fees are now common and vary widely from site to site. These additional fees are often not revealed until you reach the very last stage of the booking process.

Consolidator airfares are fares where an outside agency such as an online travel booking site has bought a block of seats on a particular flight or flights at a large discount and they then resell those seats to the general public at a profit, but still below the full market retail value you would normally expect to pay.

Consolidator fares are the best source for cheap airfares and are the cause of the biggest price differences across the web. They are most common on international flights, but are occasionally available on domestic routes.

When searching for cheap airfares, I recommend that you check at least two or three discount travel sites and maybe a couple of the major airlines.

You may already have a favorite site or sites. If so, start your search with them. I generally begin my searches with Priceline.com followed by Hotwire.com, neither of whom charge booking fees, and lastly I check CheapTickets.com. I have found all three to be excellent sources for cheap airfares. But always keep in mind no one site will have the cheapest fare every time.

If you come across a great deal, don't hesitate book it immediately! If you wait to long that great deal may not be there when you come back. There are only so many cheap seats on any given flight.

Word of warning: before booking cheap airfares, be sure you read and understand the terms and conditions for the ticket you are buying. In particular, be sure you understand the cancellation clauses.

Penalties for changing or canceling a discount flight ticket can be prohibitive. Also you should check for number and length of stopovers, flight changes, etc.

One other tactic well worth your consideration is a feature at Priceline.com called "Name Your Own Price". This can be a tremendous moneysaver, but you must first do your homework. Before making any bid with Priceline, you should have researched fares to the city or cities to which you intend to travel.

Once you have a good idea of what you should expect to pay for your flight, place a bid 20% to 40% below the lowest price you have found. It is often possible to get a rock bottom deal using this method. But be aware that your credit card will be charged immediately if your bid is accepted and you will not be able to cancel.

Booking early is always a good idea when it comes to finding the best discount airfares. But it is also true and a very often overlooked fact that a last minute booking can often score you a great deal.

If you have to travel on a specific day or date, it is obviously not a good idea to wait until the last minute to book your flight. But if you can be flexible with your travel plans, waiting until the last minute can often net you a deal that would otherwise have been unobtainable.