There's good news and even better news for air travelers.

First, the good. Southwest Airlines (NYSE:LUV) recently unveiled some especially low air fares, featuring $99 or less for a one-way ticket to any of its domestic destinations. Now, the better: Southwest is extending its low-fare availability through Aug. 7, though you probably need to book before then. (These extra-low fares are also good seven days a week right now, unlike many past sales.) Better still, other airlines, such as AMR's (NYSE:AMR) American Airlines and America West (NYSE:AWA), are also jumping in with discounted prices.

Keep in mind though, that:

  • Southwest's "special" fares are scheduled to expire on March 4.

  • Other airlines that are matching the low rates offered by Southwest and JetBlue (NASDAQ:JBLU) won't do so longer than they have to.

  • Some experts predict that prices will only increase as summer approaches and when it arrives.

  • Some airlines charge a lot if you want to change your ticket later, so either be very sure of your desired travel times when you book your flight or find out exactly what costs you'll face if you need to make a change.

Of course, when seeking out low fares, don't forget the Internet, where deals for travel outside the U.S. also abound. (If you're a high-altitude dining enthusiast, whet your appetite at for meals served on various airlines.)

And finally, although you might be excited to see low air fares, put your investor hat on for a minute and think about what these occasional fare wars mean for the airlines. They don't tend to boost profits. The airline industry has long been a notoriously poor performer for investors, with just a few exceptions, such as Southwest. Not only are fare wars an issue, but so are volatile fuel prices, the cost of empty seats, weather-related snafus, expensive equipment, and other factors. So perhaps book a ticket, and buy stock in some other industries.

For gobs of travel tips and advice, drop by our Best Travel Spots/Tips discussion board (a 30-day free trial is available, so give it a whirl).

Longtime Fool contributor Selena Maranjian doesn't own shares of any companies mentioned in this article.