DALLAS — Every major airline except Southwest Airlines Co. gives customers the ability to book flights directly from the home pages of their Web sites.

So, with Southwest's first major redesign of its Internet presence in nearly five years, you might think that home-page booking would be the first thing Southwest's Web designers would add.

But they didn't.

As on the old site, Southwest's new home page still makes customers tap a link to get to booking, flight schedules and other travel functions. But the reservations link is much more prominent and opens a window in an instant, without requiring another full page to load.

Anne Murray, Southwest's senior director of online marketing, said Southwest asked customers, both frequent and infrequent, whether they would prefer that the home page have the flight booking function open for reservations.

"It was very clear in the usability study that it wasn't an even decision on preference, open or closed," Murray said Sunday.

Southwest officials decided to leave the function closed. However, they may let customers set preferences to have the booking window be open when they go to the Southwest home page, Murray said.

Getting the Web site right is important to all airlines, but probably none more so than Southwest. In 2005, only 11 percent of its tickets were sold by travel agents, and just 15 percent by Southwest's reservation-center agents.

Today, the Dallas-based carrier gets 70 percent of its revenue from passengers who book their trips online at the carrier's Web site.

Southwest, which activated its Web site in March 1995, was one of the first carriers to go on the Internet, following Northwest Airlines Inc., Air South and a handful of others.

In its first year, Southwest used the site to sell its image and provide information. It didn't add a booking function until April 1996. Even today, a primary reason for the site is that "we like to introduce you to the brand," Murray said.

With the redesign, "we feel like we've struck the right balance between letting you see the brand, and then giving you the ability of getting to the most frequent travel tools you need," she said.

Southwest.com has about 10 million unique visitors a month, according to the research firm Nielsen/NetRatings, which measures online audiences. "Most people's reason for visiting Southwest.com is to book a trip or service a trip they've booked," Murray said.

The old site, which was replaced at midnight Sunday, actually gave visitors three places to go to book a flight: A "Reservations" button at the upper left, a "Book Travel" button with a suitcase icon in the middle and a "Book Air" hyperlink toward the bottom of the page.

According to Southwest, more than eight of 10 visitors chose the reservations button.

The new site is less cluttered than the old, with fewer links to click. Murray said the revamp isn't so much about content as it is how the content is organized. She likened the old site to a smaller house that had a lot of additions over the years.

"Based on our knowledge of our customers, we feel like we've made a nice transition," she said.