For example, airlines can offer discounts on low-demand flights, where the flight will likely not sell-out.

Each class of service includes certain amenities not offered on regular flights.

Airlines doubled the number of seats offered on flights into Colorado ski towns last winter.

Bistro is a snack service, offered for coach passengers on flights of around two to three hours.

Hot meals are offered on flights lasting longer than two hours.

And Qantas, the Australian airline, will offer the screens on certain flights starting next month.

Wine and beers are also offered on international flights.

Southwest has never offered more than cookies, pretzels and chips, even on long flights.

Refunds are being offered on flights from Sept. 11 to today.

Orbitz is also offering more information on international flights, particularly to Mexico and the Caribbean.