Bestfares has been around for more than 26 years, and we have never seen so many changes in air travel as we have in the past months. With all of these changes, travelers are left confused about the true cost of flights. You'll have to add the cost for assigned seats, checked luggage, food and beverages, and any new fees with your ticket to get your real cost to travel.

With the airlines looking to increase revenue, they are leaving no stone unturned. US Airways is now charging for "choice" seats, which they define as the aisle and window seats in the first several rows of coach class. Northwest has been charging for premium seats for a while.

Discount carrier Spirit has taken a la carte pricing to a new level. The airline was one of the first to charge for checked luggage, soft drinks and pillows, and is now charging for all seat assignments made in advance. For each segment the charge is $15 for an exit-row seat, $10 for a window or an aisle seat and $5 for a middle seat. US Airways recently announced a charge of $2 for sodas.

We will still see sales, but the only way that things will look brighter is if the cost of oil decreases. Even if oil does go down, these fees will already be in place. It is unlikely they will go away, so travelers have to be more informed to be able to compare flight costs.

The spoiler for all these add-on fees is Southwest Airlines. They have no change fees, you can check two bags for free, and kids fly solo for free. They still have more fuel efficiency than other airlines, so their costs are lower. Southwest can put a plane in the air seven times per day, compared to five times on other carriers, so they can have up to 40 percent more flights because they have a fast turnaround.

Because of the rising costs of travel, purchasing tickets during sales is more important than ever. AirTran has launched a sale to U.S. cities and Puerto Rico for travel through Nov. 5. Tickets must be purchased by July 1 for travel no earlier than July 11. One-way fares from Dallas include $89 to Burlington, Vt., $99 to Milwaukee and $149 to San Juan. Taxes and fees are additional.

While other carriers have matched these fares in many markets, you'll need to tally the various fees when comparison shopping. AirTran still allows one free checked bag, but they do charge $6 for an advance seat assignment on sale fares ($20 for exit-row seats). Contact: 1-800-247-8726; www.airtran.com/sale.

Tom Parsons is publisher of Bestfares.com.