Third-party travel sites such as Kayak, Expedia, Cheap-o Air, and Hopper are online travel agencies with metasearch engines. Use their search engines to find flights, but you will come to regret purchasing flights, hotels, or other travel services offered through online travel agents. It took one horrible experience for me to learn this very expensive lesson. I bought my cheap flights on United through Expedia. The first leg of the trip was delayed so long, I missed my connection in Denver. United staff instructed that all passengers in this same situation proceed to Customer Service for rebooking.

I stood in line for what seemed like hours, only to reach the podium and learn that since I had not booked my flight directly with United, I would have to contact my travel agent for help. I had no choice but to purchase a new, super-expensive ticket on the spot and deal with Expedia later. What a nightmare. I never did get a refund, forget any satisfaction. But I did learn a very important lesson: Use third-party search engines for information, but always book directly with the airline.

While this strategy won’t work for you if your travel plans are rigid—can only get specific days off, for example—being flexible with your travel dates means cheaper plane tickets. Look at the difference in price if you change your departure and or return dates by a day or two. Online travel sites such as Google Flights, Hopper, and SkyScanner provide convenient tools that allow you to play travel agent by exploring different dates, destinations, and prices.

Red-eye flights, which depart late at night and arrive early in the morning, are usually cheaper than regular flights due to their less desirable travel times. Although it can be tiring to wake up in the middle of the night for a flight, there are a few advantages beyond cost savings. Red-eye flights often offer the benefit of fewer crowds during TSA screenings, providing a smoother and quicker airport experience. Several airlines such as Frontier and Spirit, have become what is known as a la carte carriers. While they may offer a bundle option you pay a separate fee for everything: ticket, seat, carry-on bag, checked bag, water, etc. It can be frustrating. But crossing these airlines off your list can be a big mistake.

The secret here is to take the entire cost of the flight—all items added together—for your comparison. And then whittle down as you can to get to the barebones cost. Take the cheapest seat. Get everything into one “personal item,” which even these airlines allow you to carry on for no fee. Learn about the airline’s specific quirks and requirements. Find a way to comply, and you just might save a lot over other options. To land more affordable plane tickets, consider expanding your search to include nearby airports, particularly if your departure or destination city is in proximity to major connecting hubs. Major airports often offer lower-priced tickets compared to smaller ones. Just make sure you calculate transportation and accommodation expenses to assess whether the savings outweigh the additional travel time.