When searching for airfares, too many consumers put on blinders when choosing an airport to fly from or to. But that can be costly.

Let’s say you need to fly to Detroit from New York’s three major airports. Searching recently for May travel, I found nonstop fares on United from Newark around $300 round-trip with tax. American had a few flights for $135 from Laguardia, and Jetblue had seats ranging from $233 to $279 round-trip from JFK. But were you to drive or take New Jersey Transit to Trenton and fly from there, Frontier Airlines would fly you nonstop for $78 round-trip. Frontier also flies to Florida from Trenton at fares that are often half or less than from Newark or Philly.

Another example: Delta was recently charging $207 round-trip to fly from New York’s JFK to Atlanta for May travel. But Southwest had fares as low as $156 from Long Island’s Islip Airport. Not only is Islip less hassle than JFK, with cheaper parking and shorter security lines, but if you live on Long Island anyway why schlep into Queens just to pay more? Plus, of course, you get two free checked bags on Southwest.

Were you needing to fly from the New York area to Ft. Lauderdale in May, a one-way flight on Jetblue leaving on May 29 was going for $169 recently. But nonstop from Newburgh, NY? $135 on the same date. Again, if you live north of the city anyway why drive to JFK?

So think alternate airports, no matter where you’re flying from or to. Recently Delta had a sale to Sydney, Australia. It was charging $916 round-trip from many smaller airports, such as Harrisburg, PA and Augusta, Georgia . But from Atlanta, just a two hours drive from Augusta, the fare was $1800 on the same dates.

And it’s not just “from" airports. If you’re flying to Tokyo, you have two airports to consider: the better-known Narita but perhaps closer-in Haneda will cost less. Headed for London? Check Norwegian.com’s fares into Gatwick instead of fares into Heathrow https://www.airfarewatchdog.com/cheap-flights/to-london-england/1693/?airport_code=lhr. You could save hundreds.

One way to research alternate airport airfares: check the airlines’ route maps. Here’s a handy list.