Judging by most reviews, this is a terrific app, even if it is very expensive: $90 per year.If you intend to download it, there are some things you should know.1. You can opt for a seven-day trial period, BUT you will need to enter your credit card AND billing will automatically start when the trial period is over, if you don't--or forget to--cancel. Put a reminder on your calendar!2. The app has limitations. If you are familiar with the Air Traffic Control (ATC) system in the U.S., you will understand those limitations and why they exist. To explain this in a ridiculously simple way, ATC has two parts. One is the airport environment and the other is the rest of the U.S. airspace, the enroute environment. This app only tracks traffic and communication in the airport environment. It would be nearly impossible for it to track communication beyond that, because the enroute environment comprises hundreds of sectors, each with its own set of frequencies. While there are many apps that can track aircraft in the enroute environment, there will probably never be an app that can track all the communication that takes place between flight crews and controllers there. All the different frequency changes through all the sectors that aircraft pass through as they navigate from one airport to another would be nearly impossible to follow without some very expensive infrastructure.Bottom line: This app is not perfect, but it does a pretty good job following aircraft in the immediate airport environments of the airports that are covered. The recording feature is great, as you can go back and replay communications between ATC and specific airplanes. This feature also is not perfect, but it's pretty good. Is the app worth $90 a year? You have to decide that for yourself. I've signed up for one year. Time will tell...