Everyone loves a good deal. Almost everyone loves to travel. It only makes sense that the intersection of the two, in good travel deals, would appeal to a very wide audience.

Airlines, however, have made finding a good deal difficult. In 2008, airlines began charging fees on checked baggage. Although they suffered from bad publicity at the time, the airlines knew that if they held their ground, passengers would eventually accept the additional fees. They were right. A generation of travelers has grown up with these fees and now accept them as part of the cost of flying. These baggage fees have turned into a $5 billion profit center for the airlines.

Similarly, shortly after the terrorist attacks and wars in the Middle East caused the price of oil to spike in the early 2000s, airlines imposed “fuel surcharges” on all airline tickets. Even though the price of jet fuel has stabilized and crude oil costs less than a third of what it did at its peak in 2008, the fuel surcharges (now called carrier fees) are still assessed on every airline ticket.

These fees and surcharges make it that much more important to find the best fare possible. Here are some ways to find low-cost airplane tickets:

Be Flexible About When You Fly

Supply and demand dictate the price of airline tickets. Whether an airline sells one ticket or 140 tickets on a flight, that airplane has to fly. The airline has to make sure that flight is as profitable as possible because fuel costs, crew expenses, and taxes must be paid regardless of the number of passengers. Consequently, fares will always be lower on flights that are undersold, and higher on flights that are oversold.

Certain days of the week and times of year are less expensive to fly. These will vary by destination, again according to supply and demand. For example, flights to Chicago for Presidents Day weekend might be cheap, while flights to Miami for the same weekend in February might be very expensive.

Most people who travel for work or pleasure fly at the beginning of the week or the end of the week. As a result, Tuesdays, Wednesdays, and Thursdays usually see fewer travelers (and fewer airline tickets sold) than Mondays and Fridays. Airlines will often cut prices to sell tickets for flights in the middle of the week to try to fill those airplanes. Flying on a holiday, like on Presidents Day, can save money since most people prefer to fly before or after a holiday.

Unfortunately, burglars can also use the popularity of Friday through Monday travel to target your home. A home burglary occurs every 13 seconds in the United States. Many of these burglars case your home and your social media timeline to make sure you are not home when they strike. When you travel, make sure your social media is set to private or that you avoid posting about your travels until you return home.

Use Online Resources

Search sites for airline tickets provide a wealth of information about ticket pricing. Kayak, for example, shows pricing trends so you know whether you should buy or wait to buy based on whether the ticket price has increased or decreased.

Skyscanner provides information on the carbon output of flights, so you can account for the environmental impact of your flight choices in addition to the price. And Travelzoo allows you to search over a range of dates to find those hidden cheap flights on a Tuesday morning that you might otherwise miss.

Be aware, however, of scam sites that are not real travel booking sites. Scam sites collect your personal information and either use your payment card to run up bills or steal your identity to obtain new payment cards and credit accounts. Do your research on these sites and, above all else, be wary. Nearly 50 percent of consumers think that their security habits make them vulnerable to identity theft or other information frauds.

Time Your Purchase

As mentioned above, Kayak offers a feature that allows you to see the price trend for airfares. However, these price trends may be influenced by many factors, such as holidays, travel seasons, natural disasters, and oil prices. Summer, for example, has higher airfares to tourist destinations, while airfare may drop after a hurricane or other natural disaster.

Barring unexpected events, the window for finding good deals on domestic flights is usually one to three months before the flight and two to eight months for international flights. One strategy would be to begin monitoring airfares before this window begins to get an idea of the starting price. This allows you to identify a good deal as you monitor the airfares during the recommended window. But beware of waiting too long. When you see a price you like, you should snap it up because ticket prices can jump suddenly.

Check Regional Airports

Sometimes you will be able to fly into another airport close to your destination and rent a car or take a train for less than flying direct. For example, Sanford Airport, 24 miles from Orlando, is often cheaper to fly into than Orlando International Airport. Likewise, airlines often have less expensive fares to Baltimore than Washington D.C. Since Baltimore and Washington are connected by rail, flying to Baltimore is often a cheap alternative to flying directly to the nation’s capital.

Some airfare booking sites allow you to search for alternative airports. Checking the box to include regional airports in your search can save tens, and sometimes hundreds, of dollars on airline tickets.

Finding good deals on airfares is facilitated by good online tools. Moreover, knowledge about the days of the week and times of the year to travel, as well as alternative airports available for travel, can save you money the next time you fly. You might even save enough to stay an extra day at your destination.