When it comes to searching online for airfare to Europe, it’s tough to know where to begin in an ever-expanding sea of travel sites. Here, in part 2 of our 2-part guide to finding the right flight online, we cover the best resources:

First stop: Matrix. This is ITA Software’s public airfare search engine, and it also happens to power many popular travel sites and airlines’ reservation systems. What you can’t do with Matrix: Purchase tickets directly. What you can do: Download a mobile airfare shopping app for iPhone or Android called OnTheFly. Use an interactive calendar to explore date ranges. Refer to color-coded time bars to compare flights at a glance.

Like Matrix, Fly.com, Kayak.com, and Bing.com are so-called metasearch engines. This means you can enter your search criteria in one place and simultaneously get results indexed from multiple engines. These sites are highly efficient, but again, you can’t book tickets directly. Here’s how the three sites are different:

—Fly.com indexes just flights: its data comes from airlines and major travel sites (including discount and international flights, online travel agencies, and airfare consolidators).
—Kayak.com also indexes flights—plus hotels, car rentals, and vacation packages.
—Bing.com is slightly different in that it’s an actual search engine, or “decision engine”, in Microsoft’s words. Its travel search tool, Bing Travel, includes the cool bonus of offering price predictions for each fare (Is the fare likely to go up or down?)

Cheapoair.com functions similarly to the other metasearch travel engines in that results are culled from multiple data resources and reservation systems, but it’s a one-stop shop: Tickets can be booked directly though Cheapoair.com, either online or by phone, 24/7. Its also a full-service travel agency, with deals on hotels, vacation packages, car rentals, and airport parking.

Momondo.com is a great bet for finding cheap airfare to and within Europe. This Denmark-based aggregator indexes more than 450 travel sites—including major booking engines, airlines, and discount European airlines (an inexpensive choice if you don’t mind making a connection and possibly paying additional baggage fees). It also features city guides and a traveler blog.

Yapta.com will actually help you to pinpoint the best time to book by tracking fluctuating prices, and even better, enable you to take advantage of many U.S. airlines’ “guaranteed airfare policies”. According to this policy, if the price of flight you’ve already booked goes down, you may be eligible for a refund. Yapta will track the price of a flight you’ve booked, and alert you if it drops below the purchase price. Word to the wise: Refunds apply only if you book directly through the airline!

Along similar lines there’s Airfarewatchdog.com. What makes this site unique is its staff of dedicated “Dealhounds” (yes, real people!) who are literally sniffing out the fare sales for you. You pick your home airport, and then Airfarewatchdog.com will email you when prices go up or down.

Also worth a mention is InsideTrip.com. It’s an airfare search engine, but it’s unique because each itinerary is awarded a TripQuality score based on 12 criteria: security wait time; legroom; aircraft type; aircraft age; historical load factor; connect time; routing quality; lost bags rank; and gate location. In addition, it provide a FinalAirfare calculation—an estimate of bag and drink fees prior to departure.

Finally, if all of this just sounds like way too much work, consider Tripology.com. This is a free service that puts you in touch with certified Travel Specialists: By submitting a Trip Request online you’ll receive up to 3 Customized Trip Itineraries; you then select the one you want and book your trip.

Photo courtesy AMagill @ Flickr

Find the right flight!

Securing the perfect villa for your desired dates is just one piece of the travel puzzle: Now you need to find a flight. Here’s part one of a two-part guide to help you book the right flight online:

Let’s start with basics. Is your priority cost or convenience? Here’s a scenario to consider: I’m renting a villa in the Chianti in June for two weeks with two small children. To minimize parental headaches, I’m flying direct. I’ve booked a Delta flight serviced by AlItalia from LAX to Rome’s Fiumicino. From there, I’ll rent a car and drive to Tuscany (3.5 hours).

Now let’s say the kids are staying home with grandma. In that case I might find a more competitive rate by flying a carrier such as Lufthansa into Munich, a large, user friendly international airport with complete services, and then booking a connecting flight to Rome on a local discount airline such as Meridiana, Air Italy, EasyJet, or Blu-Express. One note of caution here: Baggage restrictions on smaller airlines are often tighter than those on major carriers; be sure to check weight limits and/or baggage charges on individual carriers’ sites before you purchase! You may even want to think about traveling with just a carry on, if possible. For alternative transportation there’s the train—a convenient, relaxing, and certainly less expensive option. According to RailEurope I could take the City Night Line, for example: The train leaves Munich at 9:00 PM…and arrives in Rome at 9:00 AM the next morning. Not too shabby!

Before you get down to searching, here’s a few more helpful tips:

—Should you pounce on tickets in February if, say, you’re not traveling until September? Depends. It might sound like a no-brainer, but it’s important to consider that the cheapest seats sell out first. Waiting until the last minute isn’t necessarily going to save money, especially in those last 2 weeks prior to your departure (when prices tend to be inflated). On the other hand, by buying far in advance you may miss eventual price drops. A good rule of thumb is to book 1-5 months in advance of your departure date for best price and selection. You’ll also find the best fares during business hours—when most people are online.

—Is there a cheaper day of the week to fly? Yes. According to Rick Seaney, CEO of farecompare.com, traveling on weekdays to Europe is cheaper than weekends (FYI: Wednesday is your day to save if you’re flying domestic).

—Consider the high and low European tourist seasons. Peak periods, such as summer (late May – late August) are generally more expensive. Late October to mid-March is considered the winter season and is typically more affordable; same goes for late March to mid-May (though Easter week may see some spikes). Fall (mid-September to late October) is also low season.

—Flexibility is key! If you’ve got wiggle room on your dates or arrival/departure airport, you can find the best deals.

Photo courtesy of xlibber @ Flickr