Smooth-flying Continental trounces the competition in the Airline category of the latest PowerRankings by Forrester Research, Inc. (Nasdaq: FORR). Forrester PowerRankings combine survey data from online consumers and unbiased shopping tests to provide objective rankings of the leading eCommerce sites in various categories. Following Continental are Northwest, American, Alaska, Southwest, United, US Airways, and Delta.

Continental rises above a crowded field by offering quick online buying and a simple reservation cancellation process. Its site also allows Web shoppers to choose their seats and meals as well as book rental cars and hotel rooms. Its greatest weakness was inconsistent email response times. Northwest comes in a distant second, offering a feature-rich site and speedy replies to email inquiries. But Northwest frustrates shoppers with its separate navigation and search engines for the main site and the reservations section, and it doesn’t let customers cancel reservations online.

“Once again, Continental wins the PowerRankings Airlines category. But the difference from last fall is that this time it broke away from the competition,” said Tom Rhinelander, senior analyst at Forrester. “Continental beats the competition at delivering what online travel shoppers are looking for — a site with a simple and quick way to purchase tickets, useful features and relevant travel content, and good customer service.”

Third-place American offers a home page with a convenient calendar that, when clicked on, automatically fills in flight dates, and its customer service was quick to reply to email questions. However, the site suffered from server errors and a laborious checkout process. Southwest comes in fourth, offering a bare-bones online shopping experience. The site lacks a search engine, flight status information, and email support. But cost-conscious travelers flying to locations served by Southwest may not mind, given the fast buying process, low prices, and near-instant answering of phone calls.

“Southwest’s site matches the airline perfectly,” added Rhinelander. “Customers may not get flight status information on the site or a meal other than peanuts on the plane, but they do get a fast and functional site and inexpensive fares.”

Alaska Airlines comes in fifth, offering speedy ticket buying, but its customer service is slow and the site is missing features like terminal maps and integrated car and hotel booking. Landing in sixth place, United offers a useful search capability, but lacks helpful customer service. An arduous online buying process and server errors leave US Airways in seventh place, while last-place Delta is criticized for inconsistent navigation and server errors.

For the updated PowerRankings, Forrester surveyed 19,000 consumers from Greenfield Online’s 600,000-person online panel. These consumers identified the most recent eCommerce sites that they purchased from and rated their experiences. A team of Forrester shoppers then evaluated the shopping experience for sites with a statistically valid number of consumer respondents, performing a series of rigorous tests in six areas. The consumer data and Forrester shopper scores were then synthesized and weighted, with consumer views accounting for two-thirds of the overall PowerRanking. A complete set of PowerRankings results — both consumer and Forrester shopper data — are made available to all ranked companies for no charge.

In the coming weeks, Forrester will be announcing results in additional PowerRankings categories. Additional information about each of the categories, including a complete set of rankings and scores, can be found at the PowerRankings Web site — powerrankings.forrester.com.