Ancillary fees, the anathema to travelers everywhere, are on the rise and bigger than ever. In the first quarter of 2011 alone, airlines earned $1.38 billion in ancillary revenue. Airlines claim the fee increases help them keep ticket prices lower, but critics denounce the behavior as exploitative and greedy.

With a view to transparency, the U.S. Department of Transportation passed a rule in August requiring airlines to list all ancillary fees and bag fee increases on their websites. Still, with seemingly ever-changing rates, it can be difficult for travelers to stay up to date. Here are three ways to avoid the most egregious fees and avoid sticker shock.

That “free” frequent flyer award ticket? It isn’t. 9 out of 13 major U.S. carriers will charge you to use your frequent flyer miles to book a “free” ticket – as much as $100. The good news is that some airlines offer reduced fees for booking online or way ahead of your departure date - some require up to 180 days notice, but others are only 21 days.

Want to take an earlier flight home from your meeting? It’ll cost you. This is one of the most irking and hardest to avoid for business travelers. When business finishes up ahead of schedule and you’d like to take an earlier flight home, changing your ticket at the airport could mean up to an extra $150 for domestic flights and $300 for international. Depending on how badly you want to get home, it might be worth the fee to avoid waiting around the airport for hours until your flight.

Pack light for international flights. Three major U.S. airlines currently charge $400 and up on heavy baggage for international flights - the single most expensive ancillary charge to date. Pare down your packing list, or consider shipping heavier items to your destination to avoid an expensive surprise at bag check.

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    Though not always possible, a good way to avoid most of the smaller baggage and nitpicky fees is through frequent flyer status. Although the base price of a ticket on another airline may be cheaper, when you add in all the fees, airfare on your preferred carrier is often a better deal (though you may have to do the math to justify the purchase to your travel department).