Free Kayak Pro Travel Planning App on iTunes

Kayak Pro is said to be the best mobile travel app out there but it has been available from iTunes for $1. I, for one, don't particularly like paying for apps because there are so much apps out there that you can get for free. But I saw that you can get it for free which has flight and car search, hotel search and booking, a flight tracker, and "My Trips" which makes your itinerary very accessible. But with the Pro version, you can get all that and airport terminal maps so you won't have to get lost navigating towards your correct gate when you are overseas and don't understand the signs. That said, I don't think the airport terminal maps is non-negotiable so I settled for the free version. Even though I'd have to endure ads, it has performed quite well in all other aspects.