When planning your travels, one way to save is to fly from a cheaper airport.

So what makes an airport a more or less expensive option?

First, look for presence of the legacy airlines, like American, United-Continental, or Delta.

If one carrier dominates the airport, that means less competition, which can translate into higher prices.

Just look at some of the most consistently expensive airports in the country, like Newark Liberty, where Continental dominates the flights from this airport.

Smaller, regional airports like La Crosse Municipal Airport in Wisconsin tend to be overpriced because they’re the only option. Again, less competition means higher prices.

Look for the presence of low-cost carriers. Milwaukee’s General Mitchell Airport, which is served by multiple low-cost carriers, is about $60 cheaper than nearby Midway and about $75 cheaper than O’Hare.

Some of the most affordable airports are areas that are popular among both business and leisure travelers, like Vegas, Orlando and Fort Lauderdale.

That’s where lower fares help increase traffic, and the climate means fewer delays and cancellations which raise operational costs.

For more help on finding inexpensive airport options, check out America’s Best Alternate Airports.

Get more money-saving tips in our Budget Travel section.

And check out the rest of our Daily Travel Tips here.