The newest breed of travel search engines

Checking multiple Web sites to find great vacation deals is so old-school: the newest breed of travel search engine can trawl hundreds of airline, hotel, car-rental, and trip-consolidator sites simultaneously—collecting the top bargains available on the Internet at warp speed and free of charge (users go on to purchase at vendors’ sites). Each of these travel aggregators works slightly differently from the others, so, using a test run from Chicago to San Francisco, we’ve investigated which does what best. Here’s how the new kids on the block stack up.

Searches Routes between 55 U.S. departure cities.

Strengths Unearths good deals and predicts the cheapest time to buy an airfare. Check here first, no matter where you actually buy.

Weaknesses Only covers round-trip fares and is not (yet) compatible with all browsers.

Lowest Prices Flight: $448, on American Airlines. Hotel: N/A.Car: N/A.

Try This The interactive fare grid pinpoints the cheapest day of the week— as well as the time of day—to buy and to fly.

Searches At least 105 airfare and hotel sites.

Strengths Routinely turns up the lowest fares, Searches the fastest, and sends real-time fare alerts to your desktop.

Weaknesses Finds fewer direct flights than other sites. Some airfare and car results don’t include taxes or fees; none of the hotel prices do.

Lowest Prices Flight: $389, American. Hotel: $76, at the Rodeway Inn Downtown. Car: N/A.

Try This The satellite-enabled hotel maps detail all of the nearby attractions.

Searches More than 120 airfare, hotel, car-rental, and cruise sites.

Strengths Finds some of the best prices and is the easiest to use. Displays fare codes, so you’ll know which flights you can buy with miles.

Weaknesses Specific-airline and flexible- date Searches require a time-consuming registration process.

Lowest Prices Flight: $464, American. Hotel: $67, at the downtown Best Western Civic Center Motor Inn. Car: $16 per day, from Enterprise.

Try This The family category in the Buzz section contains up- to-date articles and information on travel and destinations.

Searches A total of 169 airfare, hotel, and car-rental sites.

Strengths Deals are competitive, and many foreign budget sites are included. The best choice for international bookings.

Weaknesses Sends users to several sites not designed for English-speakers; search options are limited.

Lowest Prices Flight: $445, American. Hotel: $59, at the downtown Mosser Hotel. Car: $16 per day, from Enterprise.

Try This The vacation-package search can be sorted by features and activities, such as, "aquarium" or "spring training."

Searches More than 150 airfare, hotel, car, and vacation package sites.

Strengths Fares often rival Kayak’s, and ultra-precise filters compare deals with other sites’. Good if your trip dates are inflexible.

Weaknesses Works slowly at times, and initial airfare Searches can’t be narrowed to "nonstop only."

Lowest Prices Flight: $470, American. Hotel: $58, at the downtown Best Western Civic Center Motor Inn. Car: $17 per day, from Enterprise. The activity-finding tool locates cities by themes ("amusement park," "concert") and sells tickets to listed events.

*Searches were conducted September 21, 2006, for round-trip flights from Chicago to San Francisco departing November 18 and returning November 26, and for hotels (nightly rates, based on double occupancy) and rental cars in San Francisco over the same period.