NEW YORK — Midwest Airlines and Virgin America ranked highest in overall quality among U.S. airlines in a Zagat Survey of frequent fliers released last week — but the results also showed Americans are unhappy with the industry's overall performance, especially on late and canceled flights.

Midwest, a carrier known for its fresh chocolate-chip cookies and leather seats, took top prize among economy-class fliers, with respondents praising its "extraordinarily helpful" staff and "excellent value." It is the fifth time in a row the Oak Creek, Wis.-based carrier has come out on top of the survey.

For passengers in pricier premium seats, Virgin America of Burlingame, Calif., came in first, just over three months after starting service. The carrier, which touts seat-back entertainment systems and leather trim of its own, also tied for second place in the economy category. One reviewer suggested billionaire Richard Branson's brainchild could set a "new benchmark" for domestic service.

Tim Zagat, chief executive of the survey firm, said the findings didn't come as much of a surprise.

"Midwest has been running essentially a business-class airline while charging economy class rates," he said, and Virgin is "a totally new airline, with new equipment and young, happy campers as a crew."

On the whole, though, American travelers don't appear quite so cheerful. Most of the major U.S. airlines' rankings have fallen considerably since Zagat began polling passengers in 1990, the company said.

Only Continental Airlines and Southwest Airlines improved their standings over that period.

"They exemplify what good management can do for an airline," Zagat said. "It's not hopeless."

Topping the list of complaints were flight cancellations and delays, and "feeling like you're being treated like an animal in a cattle car," Zagat said.

In addition, 60 percent of respondents said they favored a passengers bill of rights to help protect them in the event of bad or delayed service. Only 5 percent of respondents said they opposed such a law, while about a third said they didn't know what it was.

The House of Representatives passed a bill in September that would force airlines to create plans to deal with long delays and allow passengers off planes, among other measures, but the Senate has yet to pass a similar bill.

As for U.S. airports, survey respondents ranked Tampa International No. 1, followed by Denver International and Minneapolis-St. Paul International.

The worst? New York's LaGuardia.