The sky is falling.

At least you might think so after seeing how far airfares have plunged in recent months.

Ever since one of the big "legacy carriers" -- Delta -- joined the cost-cutting craze early this year, good cheap fares have been falling like spring showers. But the skies haven't cleared yet everywhere. For one thing, some airlines that style themselves "low-cost" don't always have the cheapest fares.

As much as the legacy airlines have moved to match cheaper prices from "low-fare" carriers, often a ticket's cost comes down to how much competition there is on a particular route. Another factor is that airlines are simplifying operations, and pricing is part of that.

Business travelers owe it to themselves to sit up and look around, because, in case you haven't noticed, things are changing fast, which means you've got to do your homework if you expect to benefit from lower fares.

Do your research

The most important thing to realize is that there is no single place where all of the low prices live. To find them, you've got to do some legwork.

Here are tips I follow:

  • Know which carriers serve not only your cities of arrival and departure, but your stopovers as well. Sure, you can go to your favorite airline's website and check pricing, but what you'll be missing is which other carriers fly to those connecting cities.
  • Visit the big online travel agencies, where you'll learn which traditional carriers fly to which connecting cities. But remember, those big travel websites will miss the smaller, low-fare carriers and airline Web fares. The way to find out whether the JetBlues of the world serve a particular airport is to visit those individual websites as well.
  • If surfing the Web becomes too time consuming, enlist a travel agent. Most agents also have access to a powerful reservations database -- a global distribution system (GDS) that links the various travel suppliers globally. While a GDS won't necessarily be linked to every low-fare carrier, savvy agents may be able save you money by using other resources, like airline consolidators, that you weren't even aware of.

The Internet is so empowering that it gives business travelers the impression that all of the pricing information which exists is right there for them to see. The truth is that many of the airfares are there, but a fair share of them aren't.

For example, "bots," or Web agents that surf websites to gather information, in this case, prices from the low-cost carriers' websites, can save you the trouble of searching each site. The problem is some low-cost carriers have turned off the bots, as have some travel websites. So while much of the travel information that once was the province of the GDSes and the airlines is now widely available on the Net, it's not always easily accessible. The other thing to remember if you use a bot to save money is that some make their money by adding a fee onto the prices you see.

Shop smart

An amazingly low airfare found on a travel website should be even lower on the airline's website. That's because some travel websites make their money by adding fees, while the airlines don't.

Of course, the Internet is a double-edged sword. The more you look for savings, the more of your own time you're spending. At some point you have to ask yourself, What price do I assign to my time?

Which is why many travelers end up back at the traditional travel agent. Not only are they be able to spend their time on other things, they're also tapping into a professional with experience and information access they can never hope to have.

Bottom line

If you're like me, you'll know which simple bookings you can do yourself and which complicated ones you really need an agent to do. Whichever way you go, what's important to remember is that you need to do your homework.