Earlier this week, Kayak.com claimed to be the first to launch a new weekend airfare search tool that allows users to find domestic and international flights departing and returning over weekends in a given month. It's a useful tool (more on its features in a minute), but it's certainly not the first of its kind. Orbitz.com has been offering almost the exact same thing for years.
It had been my understanding that Orbitz's weekend flex search didn't allow for international flights, but in my research today I discovered that the site does. That makes it easy enough to compare Kayak's and Orbitz's flex searches for a weekend getaway to Paris in September (who doesn't want to jetset to the City of Light, after all?).
So, for the sake of comparison, let's suppose I'm off to Paris. Kayak allows you to search by preferred day of the week from Thursday through Monday for all weekends in a month—a feature Orbitz does not offer. However, Orbitz leaves Kayak in the dust with its other features.
Orbitz's weekend search tool doesn't give you the option to choose a specific day of the week to fly; instead, it provides a chart of the lowest fare for each day available for weekend travel. This way, you can scan the chart and choose which days and prices are most preferable to you. I also found that once you choose a flight with Orbitz, you will be alerted to how many tickets are available at that price.
Kayak, by comparison, displays the lowest prices for every weekend based on your chosen weekdays on the search page. Many people may find this more efficient than scanning a chart, but I think if you're flexible enough to take a weekend trip, you're probably flexible enough to leave a day early or late based on price. Kayak doesn't give you this option.
I did, however, find the exact same price, including taxes, on both websites.