This was an Alexa Skill I built when I was a student pilot and was struggling to talk on the radios.
You can speak to Alexa as if you’re a pilot and requesting to take off or land and ATC will respond. The underlying architecture was based on a finite state machine. It was an interesting way to build a voice based Alexa Skill. It won the AWS Educate challenge recently.
You can read more about the technical details and problem space in two places:
Here is a quick video demonstrating the project in action: