When it comes to finding the best airfare, advice abounds. Problem is, some tips and conventional wisdom are questionable or downright wrong. Yet the myths are repeated everywhere from cocktail parties to media reports.

Of course, booking a flight is a far different experience than it was a generation ago. Instead of consumers calling an airline on the phone or using a travel agent, today it’s mostly a do-it-yourself, online task.

You can book on the airlines’ own websites and use fare-comparison sites, such as Kayak.com, Bing.com, Expedia.com, Orbitz.com, Hipmunk.com and Travelocity.com. Even Google recently got in the game with its new Flight Search feature. (Check Southwest Airlines fares at southwest.com because it isn’t listed on most comparison sites.)

As robust as today’s online tools are, airfares can still seem confusing, and they vary wildly, said Rick Seaney, chief executive officer of FareCompare.com, a comparison site that has studied years of fare data and offers tips and advice on airfares.

“Most consumers know they can shop at 10 a.m., 1 p.m. and 5 p.m. and get three different prices for the same flight,” he said. “The playing field for the game is pretty simple. The airlines’ job is to make the most on each seat on every flight. The consumer’s job is to pay the least for each seat on every flight they take. Somewhere in between is what actually happens.”

Sure about that?

Here is a sampling of the bad advice and common myths about booking a domestic flight, along with some better tips.

• “Shop on weekends.” This advice is more likely to get you the worst fare than the best. FareCompare’s analysis of airline pricing shows that 3 p.m. Eastern time Tuesday is the optimal time to start shopping for airline tickets. Why? Typically, one airline starts a sale on Monday night. Other airlines, being price copycats for competitive reasons, follow suit on Tuesday. The reservation system is updated by about 3 p.m. Tuesday with the maximum number of cheap seats across the most number of airlines. Sales typically end by Thursday night. “The window of time to buy is between Tuesday and Thursday night, generally,” Seaney said. That’s a rule of thumb. Prices vary by airline and route for all kinds of reasons.

• “Buy your ticket very early or at the last minute.” Better prices on tickets don’t start until about three and a half months before departure, Seaney said. “People think that by being a very early bird, they’re getting a good deal, but that’s just not the case,” he said. And prices rise dramatically starting about 14 days before departure. “Once you hit the 14-day mark, airlines start treating you like a business customer who can afford more.”

The cheapest days to fly are generally Tuesday, Wednesday and Saturday. They’re cheaper because they are typically slower days for the airlines. That has an added bonus: You’re more likely to travel in “poor man’s first class” — meaning an empty middle seat and more elbow room. Unfortunately, in recent years airlines have cut back on service, reducing the number of seats and your chances for an empty middle seat.

• “Use a travel agent.” Using a travel agent can be a good idea for a variety of reasons, especially for complicated or unusual trips. But for booking a domestic flight, not so much. For the most part, travel agents don’t get commissions from the airlines anymore. With a basic computer search, you have access to all the same tools, anyway.

• “Airfares are based on distance traveled.” Competition drives the price of a ticket more than anything. That’s why consumers can see a ticket from New York to Boston for $600 and a ticket from New York to Los Angeles for $300. Jet fuel is a huge expense for airlines, but competition drives pricing more than the prevailing price of crude oil, Seaney said.

• “Major airlines provide the best service.” Quality is in the eye of the beholder for any single flight, but satisfaction surveys, including complaint rankings by the U.S. Department of Transportation, consistently show most of the majors score relatively poorly. Southwest Airlines is an exception, scoring well, along with several smaller discount carriers.

• “You’re out of luck if an airfare drops after you book your ticket.” Actually, quite a few airlines will refund the difference if you ask. For some airlines, the price drop must reach a certain threshold before you’re eligible. The highest threshold is for the biggest airlines, which require a price drop of at least $150 — to cover a $150 rebooking fee — before they will issue a refund. Typically, airlines require that you purchase the ticket directly through the airline to qualify for a refund, which might be in the form of a credit or a voucher for a future flight.

Might be on to something

And here are a couple of tips that might sound fishy but actually have some merit.

• “Try standby rather than pay a change fee.” This is worth a shot. Sometimes you can get a confirmed standby seat, which might cost you $50, rather than paying a $150 change fee to rebook a flight, Seaney said.

• “When shopping for multiple passengers, shop for a single seat too.” This is actually a good trick, Seaney said. If you have a party of four, for example, you might find a single seat costs $200, but seats for four people cost $300 each. It’s a quirk of airline reservation systems. “Everybody who is on the same itinerary has to have the same price,” he said. “So if you have four people and there’s one cheaper seat, they’re going to bump all four to the next higher price.

So, by shopping for one, you can easily tell whether there are some cheaper seats on the flight.” Then you can split your itinerary to capture the cheaper seat.

Cool tools

• InvisibleHand: This web browser plug-in stays hidden until you’re shopping for something, including airfares. Then it shows up as a bar across the top of your screen and tells you where you can get the item for less. www.getinvisiblehand.com

• Bing Price Predictor: Formerly called Farecast, this tool analyzes past airfare pricing trends to predict whether the flight you’re interested in will rise or fall in price, which helps answer the nagging question of whether to book now or wait for a price drop. www.bing.com/travel

• Yapta: This site does two primary things. It will track airfares before you buy, and it will help you get a refund if a fare drops after you buy. www.yapta.com