I dont know if kayak picks up american since they no longer participate in Orbitz or Travelocity-but they hub in dallas and are usually one of your cheaper options going to texas-but they want you to use their site to price flights.
If you are flying to Texas, you might want to try Southwest Airlines. They only sell on their website. With Southwest, bags fly free!!! Something to consider when comparing costs!
Yeah, keep in mind that Kayak.com does not list every airline. I love Southwest! They are usually the cheapest airfare. I wish they flew everywhere though.