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Southwest Airlines outdoes other low-cost carriers with more than 3,200 flights per day to 73 cities.

Checked luggage, something to snack on, a seat beside your companion. These conveniences, once part and parcel of the air travel experience, have been extricated and assigned separate price tags. The latest is legroom: Last week the Boston Globe highlighted the trend of airlines scrunching rows together and charging for extra inches.

This nickel-and-diming is by no means confined to no-frills airlines looking to keep fares low. Even major carriers have done away with so-called frills in the face of high fuel prices and other challenges. Ironically, some of the only airlines that don’t charge for the first checked bag these days are low-cost carriers. With the line between budget and legacy airlines blurrier than ever, frugal travelers are embracing the former.

Below are some of the best domestic budget airlines, based on research by Cheapism.com.

• Southwest isn’t sitting out of the movement toward less legroom, although it aims to cram in more passengers, not wheedle another fee out of long-legged customers. It doesn’t collect for onboard refreshments either and will check not one but two bags for free. The airline’s legions of fans cite these unexpected perks and excellent customer service in online reviews. Southwest outdoes other low-cost carriers with more than 3,200 flights per day to 73 cities. Note that this airline doesn’t assign seats, so be sure to check in online 24 hours ahead for a prime position in the unique first-come, first-served boarding process. (Where to buy)
• AirTran is merging with Southwest but earns a spot on our list in its own right. Reviews highlight courteous staff and complimentary snacks and (nonalcoholic) drinks. Even Wi-Fi is free on some flights. AirTran does charge for checked baggage and priority boarding. It counts more than 700 daily flights to more than 65 destinations, primarily in the East and Midwest. (Where to buy)
• JetBlue doesn’t always offer the lowest fares but scored highest in an annual survey of customer satisfaction (Southwest was a close second) on the strength of its aircraft and in-flight services. The airline offers beverage service and snacks gratis, and screens on each seatback broadcast DirecTV. JetBlue is shaving an inch of legroom off most seats on its smaller planes but generally still provides more space than most. Reviewers appreciate that the first checked bag is free and praise the customer service. JetBlue flies to 60 cities, with about 600 flights per day. (Where to buy)

The challenge with low-cost carriers is finding one that flies to your desired destination. Routes tend to concentrate in particular regions, leaving travelers elsewhere out of luck. All the airlines above have expanded to popular vacation spots in the Caribbean and Latin America. Be sure to note which airport turns up in a search, not just which city, as low-cost carriers often serve large metro areas from secondary airports. You may find it equally convenient (or even more so) to fly to Chicago’s Midway instead of O’Hare. However, most budget flights to the Miami area land in Fort Lauderdale, about 40 minutes away.

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