It's come down to this: Among the big, traditional U.S. airlines, one still offers free blankets to chilly passengers on any flight. The distinction belongs to Delta Air Lines. Many of Atlanta-based Delta's rivals limit free blankets to red-eyes or certain routes or have started charging for blankets as well as pillows. And Delta itself isn't promising how long its free-blankets-for-all policy will last. American Airlines on Saturday started charging coach customers on domestic flights for a pillow and blanket pack. The pack includes a fleece blanket and inflatable neck pillow for $8, plus a coupon for use at Bed, Bath & Beyond. Passengers get to keep the pillow and blanket they pay for. US Airways also sells a $7 pack with an inflatable pillow, blanket, eye shades and earplugs. Some smaller carriers such as JetBlue also sell pillows and blankets. The trend adds to a lengthening list of fees, for everything from checked bags to food, that airlines have added to boost revenue. And it's working; last year so-called 'ancillary' revenue rose 42 percent for the industry, to $7.8 billion AirTran Airways, Delta's biggest rival in Atlanta, offers neither pillows nor blankets. 'For a majority of our flying, pillows and blankets aren't really needed,' said AirTran spokesman Christopher White. 'They're an additional expense, and being able to keep our costs low allows us to keep our fares low.' United Airlines on its domestic flights only offers pillows and blankets in economy on certain routes, such as red-eye and Hawaii flights, among others. Continental also limits complimentary pillows and blankets to flights to Hawaii and overnight flights. And even Delta doesn't hand out free bedding as liberally as in the past. While blankets are still available for all passengers, Delta only offers pillows on international flights and in first class on domestic flights. Kelly Yamanouchi writes for The Atlanta Journal-Constitution. E-mail: Kelly.Yamanouchi@ajc.com. 