Q: I could use some Travel Detective advice on this one. I heard you can schedule your flights so that you can enjoy a long stop in one city, get off, see friends, then hop back on and continue to your destination at no extra cost. Is that true? How can I do this? I'd really like to see some friends in Dallas on my way to San Diego.

–David Pardo, Skokie, Ill.

There are a few ways you can make this happen, John, but to do it right, you may have to do a little homework.

If you're an elite passenger traveling on a frequent-flier award or full-fare ticket, some airlines actually allow free stops on your round-trip ticket.

If you're not an elite passenger, try checking with a travel agent or a company like Airtreks.com. Airtreks is known for around-the-world tickets, but it can also help you in planning a domestic trip. This company specializes in multi-stop travel, so its agents have all the handy facts and figures on airport-departure taxes and on which cities are layover-friendly.

Also, check on sites such as Orbitz or Kayak, which have multi-stop flight options. The prices will depend on when you're traveling and how long you plan to spend on your layover. Chances are it will be far cheaper to book several legs on one ticket than to buy multiple one-way tickets.

If you decide to book multiple one-way tickets with separate airlines, make sure you give yourself plenty of cushion on your layover, in case your initial leg is delayed. Because guess what—if your flight is delayed and you miss your second one, the other airline won't have any sympathy for you. So if you go that route, as an added measure, consider buying travel insurance.