Airfare Expert: Save money by flying hungry

— -- Have you ever heard the term "flight-quality score?" If not, you may be paying too much for airfare. Let's see if we can fix that.

Flight quality score is a pricing decision based on several factors that determine whether passengers consider one flight more valuable or desirable than another. Think of it as a scoring system for what you pay for airfare. The airlines' technical term for it is "Quality of Service Index" (QSI), and it simply means that the more value a flight has, the higher quality score it earns, with higher quality flights commanding higher ticket prices.

What makes a flight valuable to you?

Departure time is a prime consideration for most passengers. A dawn flight is often cheapest because many passengers put a low value on having to get up at 4 a.m. to go to the airport. But that value can change, and here are a couple of examples:

Last week I checked American Airlines fares from Los Angeles to New York in July, and the earliest flight out was most expensive ($575 one-way). So why does that 'early' flight get a high value? Because it's a long flight - and on long-hauls, people value an early start. The cheapest fare for this route - $208 one-way - was for late afternoon/evening departures and the value for such flights is considered low because of the perception late flights 'waste' an entire day and/or cut into sleep time.

Let's look at mid-range flights. The most expensive price for Dallas to Las Vegas recently was a 9:45 a.m. departure; its passengers clearly value a leisurely start for a 2-hour-and-40-minute flight. An earlier flight was indeed cheaper, but the really cheap flight was at 11 a.m., for a savings of $130. Why the low value? Flights close to meal times often have less value, plus Vegas travelers may think an 11 a.m. departure eats up too much time at the gaming tables.

A good rule of thumb: Don't fly when everyone wants to fly; popular departure times have the most value and therefore generally cost you more.

What other factors go into a quality score?

The number one factor is non-stops vs. connecting flights. Typically, non-stops have higher value because of the convenience factor, so they're more expensive. That said, sometimes connecting flights cost the airlines a little more in extra airport taxes and fees, which they then pass along to passengers. However, connections usually save you money. This is nowhere more evident than on flights to Europe, where I've seen non-stop airfare premiums of 20-40%. Depending on the flight, that can mean a difference of $500 - or two nights in a nice hotel - so you have to ask yourself, what's convenience worth to me?

Other quality factors include the type of aircraft flown, day/time of week and the frequency of departures - which can be important for those of you who are habitually late to the airport.

How do I find the best ticket prices?

Take a connecting flight, and fly hungry; if you're eating breakfast, lunch or dinner on a plane - traveling at or around a traditional meal time - you're probably paying much less than those that ate breakfast at home with their family and arrived at the same time.

FareCompare CEO Rick Seaney is an airline industry insider and top media air travel resource. Follow Rick ( @rickseaney) and never overpay for airfare again.