This summer gas prices will rise just as much as the temperature, but just because the economy is heading in a downward spiral doesn't mean your vacation plans must go with it. With the proper research and the right tools, finding an affordable getaway isn't as difficult as you may think. Below are a few sites worth checking out before you book your summer vacation. Know when to travel It's common knowledge that flying during a holiday is the most expensive time to book a flight, but outside the holidays, how can you tell when you're getting the cheapest airfare? Luckily sites like AirFareWatchDog and Yapta can help. These sites track fares and alert you when prices drop. Microsoft's Farecast goes a few steps beyond the call of duty by actually recommending dates that will yield cheaper airfare so you'll never get gouged with "peak season" pricing again. Watch out for: Farecast can only predict airfare for select cities. Many European, South American, and Asian destinations are not accounted for. Compare airfares By now, everyone knows about Expedia.com and Priceline.com. While these sites are worth checking, they don't always list the best deals. To compare as many fares as possible, add sites like SideStep and Kayak to your query. These travel engines comb the Internet for travel deals so that you don't have to. Watch out for: Just because you found your tickets on Kayak doesn't mean you're buying them from Kayak. These aggregators will lead you to other sites like CheapTickets.com where you will book and purchase your tickets. Be sure to familiarize yourself with each site's terms and conditions before you buy. Look for international aggregators Going abroad? Sites like Mobissimo and SkyScanner are particularly good at finding cheap international fares due to their relationships with overseas partners. If you're going to a specific area, you'll also benefit from visiting region-specific sites like Zuji, which specializes in travel to and from Asia Pacific. Watch out for: Like Kayak and SideStep, these sites are aggregators and will point you to other sites for booking. It pays to be flexible When it comes to traveling, the more flexible your schedule is, the better the bargains you'll find. If possible, be open about which airports you're willing to arrive/depart from. Departing/arriving from less trafficked airports can shave a significant amount of money from your ticket. Likewise, flying on standby can help you save some cash. Airtech specializes in last-minute flights letting travelers purchase electronic "E-Passes", which in turn will place you on empty or standby seats. When a flight comes up heading to your destination, Airtech contacts you and all you have to do is confirm the flight and off you go. Watch out for: When flying with Airtech you won't rack up frequent flier miles. In addition, the company doesn't reveal its affiliates until after you purchase an E-Pass. Louis Ramirez is dealnews' Features editor.