Used to be, if you wanted to save money on your summer vacation,you gave up the convenience of flying and drove to yourdestination. A couple tanks of gas cost less than airfare in thosedays.

Now, with gas approaching $4 a gallon in many areas of thecountry, and some experts predicting it will reach $5 a gallon bythe end of the year, finding cheap flights online could be alot more cost effective than ever before. And when you consider thespeed and relative convenience of flying, taking to the air -rather than driving – may make more sense for your summervacation.

Still not sure? Check out an online fuel cost calculator tosee just how much that road trip will cost, versus flying.

When it’s time to find cheap flights, there’s no faster, easierand more cost-effective way than going online. Websites likeExpedia.com offer instantaccess to low-priced fares for domestic and internationaltravel.

You can also ensure you snag the cheapest airfare available byfollowing a few simple booking rules:

* Time your purchase – If your vacation dates are set in stone,book your flight as early as possible, especially during peaktravel times. Usually, as a travel date approaches, airfares risein price. Wait too long and you could find yourself paying throughthe nose or unable to obtain tickets for the travel days you need.If, however, your vacation dates are flexible and you can be readyto fly on a moment’s notice, it’s sometimes possible to score deepdiscounts at the last minute. Be forewarned, however, this is arisky game – one you might not want to play if you’re travelingwith kids who will be disappointed if you have to cancel.

* Shop around, but sensibly – You can find plenty of websitesthat claim to sell cheap flights, so it makes sense to comparisonshop – within reason. If a deal seems too good to be true, oryou’ve never heard of the seller website before, or you can’t finda phone number to call or some way to connect with an actual humanbeing when you have a problem – you may find out the deal is not sogreat after all.

* Flexibility pays off – Fares vary based on departure anddestination airports. If you’re able to drive a short distance toor from a different airport, you might find a cheaper fare. Also,when you travel makes a difference. Certain times of day are lesspopular with the majority of travelers and you might find lowerfares if you fly at that time. Likewise, certain times of year orseason might offer lower fares. For example, you can be prettyconfident travel will be brisk – and fares higher – if you fly oversummer holiday weekends, including Memorial Day, Fourth of July andLabor Day.

This summer, save your gas money for necessity traveling andconsider finding cheap flights online instead – you may just findthe savings helps defray the rest of your vacation costs.