I use kayak.com all the time... I would highly recommend it... It still has some glitches, or things I'd like for it to offer, but overall, it is one of the best flight aggregators on the internet.

For example, I get a daily email of the fares that have been searched on from my home airport to destinations across the world, and what the price was when they were searched. SO, if there are bunch of cheap fares to London, and people searched for them on kayak, then they send an email the next day.

Also, you can go right to the site, enter the desination location (World, Europe, Asia, Domestic, etc...) the month you want to travel, and it will tell you the lowest fares. Pretty cool stuff.

The problem? You can designate a "preferred" airline (which of course I use UA), but it when it sends you the email, it does not split out your preferred airline. So, you might get great rates to Europe, but it could be on another airline... You have to actually click on the link to find out if its a UA fare or not.

When you set a preferred airline, you do get to see your UA results first, which is really helpful. Honestly, kayak.com is one of the best I've found, but it does take a little work and understanding to use it to its fullest.

One of the things I really like (especially before united.bomb had a decent flexible dates search engine) is that you can set kayak to search 3 days before and after, and it kicks back the same type of results...

Feel free to PM me as I use kayak all the time if you need help.

Have a great Saturday!

H*S