Those bland sandwiches sold by airlines to economy-class passengers? They’re on the way out.

Even as the last major airline — Continental Airlines — is ending free economy-class meals on domestic flights this fall, carriers are changing their whole approach to food.

Air Canada has introduced healthy food options, like vegetarian sandwiches and yogurt parfaits, and Alaska Airlines has a new healthy snack pack. American Airlines is working with Boston Market. JetBlue is about to start selling food on select long-haul flights. Some carriers are expected to offer combination meals and other promotions similar to those available at fast-food restaurants.

And United Airlines is testing the sale of some food items sold on domestic flights, and a variety of sandwiches, in its Red Carpet lounges at Chicago O’Hare International Airport and Los Angeles International Airport.

It will also let passengers preorder in-flight food by the end of the year.

The new offerings are in large part the result of the new economics of in-flight food. Kevin Jackson, managing director of consumer marketing for US Airways, said that when airlines gave away food, “the motivation was to minimize cost.”

Now that most airlines are selling food, they have an incentive, he said, to “provide better choice and quality for passengers.”

In addition, the airlines are competing with new restaurants and take-out food businesses in the airports.

With many more options on the ground, most hungry travelers seem to be bringing food on board. A survey conducted by Forrester Research in the fourth quarter of 2009 found that 19 percent of leisure travelers and 21 percent of business travelers bought a meal or snack on a plane in the previous year.

If a free in-flight meal was not offered, only 6 percent of travelers polled in Zagat Survey’s 2009 airlines poll said they typically purchased food on-board, but 56 percent said they bought it in the airport.

Indeed, in-flight food sales are not huge money-makers for the airlines. Tom Douramakos, chief executive of GuestLogixa company based in Toronto that makes the hand-held devices and software used by most North American carriers for in-flight sales, said carriers generated a net profit of only 5 or 10 cents on a $10 sale of in-flight food.

Douramakos predicted that GuestLogix’s technology would allow airlines to offer more combination meals, including a drink, snack and sandwich or salad, an option now available on Air Canada. He said he expected carriers to distribute coupons with food or drinks bought in-flight, good for discounts on future purchases, and also to deeply discount items that remained unsold as a flight progressed. The technology, he added, will allow airlines to operate more like restaurateurs.