Airfares dip below $100 round-trip in Southwest, AirTran sales

Bargain travelers will be able to book trips for less than $100 round trip this winter.

But, to do so, they'll have book by Thursday (Oct. 11) and fly on short routes close to home. They also must be able to stick to fare-sale fine print that includes black-out dates, promo codes and a few route restrictions.

Southwest Airlines and subsidiary AirTran have each rolled out nationwide sales that drop round-trip airfares to less than $80 on their shortest routes. A number of other short routes are available for less than $100 round trip. Longer trips also are included -- Atlanta-Denver fares are available for less than $130 round trip -- but the sub-$100 fares are only found on short hops.

Both airlines' sales end at 11:59 p.m. PT Thursday (Oct. 11). The sales cover winter travel, extending through much of February. Holiday periods and certain routes are exempted.

As of 5:30 p.m. ET, it appears that at least some major rivals have begun matching the sale fares certain overlapping routes. Among those matching as are American, JetBlue, Spirit, United and US Airways.

As for the initial fare-sale details on Southwest and AirTran, scroll down for more:

Southwest
Southwest's sale covers flights between Nov. 28 and through Dec. 12 and from Jan. 7 through Feb. 14. To get the fares, Southwest customers must enter the promo code "BigDeal40" when they search for fares. The code gives fliers a 40% discount off its normal "Wanna Get Away" fares, with a round-trip purchase required.

Sunday flights are not included in the sale. Fares appear to be lowest on Tuesdays and Wednesdays. Other sale-fare exemptions include the following routes: Austin-Orlando; Detroit-Phoenix; Orlando-Phoenix and all flights to and from Fort Myers, Fla. There also are some city-specific blackout dates, such as around Mardi Gras for New Orleans and around the presidential inauguration for flights to and from Washington, D.C., and Baltimore.

Sale fares must be booked no later than 11:59 p.m. PT on Thursday (Oct. 11). The rest of the fine print is available on Southwest's website.

Sample round-trip fares (including all taxes and fees): Oakland-Las Vegas, $77; Los Angeles-Las Vegas, $77; Baltimore-Boston, $84; San Diego-Phoenix, $92; Houston Hobby-Dallas, $97; Atlanta-Denver, $127; Chicago-St. Louis, $128; Kansas City-Dallas Love, $134; Raleigh/Durham-Fort Lauderdale, $141; Seattle-Salt Lake City, $175; Los Angeles-Newark, $281.

All fares are for a Jan. 9-to-15 (Wednesday-to-Tuesday) itinerary and were available as of 1 p.m. ET on Oct. 9, 2012.

AirTran
AirTran's sale covers domestic flights between Nov. 28 and through Dec. 18 and from Jan. 4 through March 1. Unlike Southwest's sale, no promo code is required for the AirTran sale fares. Also unlike Southwest's sale, a round-trip purchase is not required and the sale fares appear to be available across most days of the week.

As with Southwest's sale, there also are some city-specific blackout dates, such as around Super Bowl for Las Vegas and around the presidential inauguration for flights to and from Washington, D.C., and Baltimore.

Sale fares must be booked no later than 11:59 p.m. PT on Thursday (Oct. 11). The rest of the fine print is available on AirTran's website.

Sample round-trip fares (including all taxes and fees): Boston-Baltimore, $90; Dayton-Baltimore, $90; Akron/Canton-New York LaGuardia, $90; Tampa-Atlanta, $90; Milwaukee-Washington Reagan National, $148; Portland, Maine-Charlotte, $170; Richmond-Houston Hobby, $218; Atlanta-Los Angeles, $270.

All fares are for a Jan. 9-to-15 (Wednesday-to-Tuesday) itinerary and were available as of 1 p.m. ET on Oct. 9, 2012.

Rivals matching
Spirit, United and US Airways had matched either Southwest's or AirTran's sale fares on certain routes. Among the routes where rivals had matched fares:

American: $129, Chicago-St. Louis
US Airways: $92, San Diego-Phoenix; $99 Buffalo-Washington; $215, Richmond-Houston
United: $99, Washington-Buffalo; $129, Chicago-St. Louis
Spirit: $72, Las Vegas-Los Angeles and $71, Dallas-Houston
JetBlue: $86, Boston-Baltimore