Most modern UAVs/drones have a dependency on using a mobile device as part of the flight systems. The drone manufacturers launch the controlling app for the drones in mobile app stores. There has been a tremendous upsurge in the number of UAVs (Unmanned Aerial Vehicle) mobile apps on the Google Play Store over the past few years. A UAV/Drone app user expresses the experience with the app by providing comments on the Google Play Store. Whereas, the developers interact with the user by posting replies to users' comments. Feedback in users' comments enables developers of mobile apps to discover issues, such as features requests, bugs to fix, and app maintenance requests, in a timely manner. The value of responding to a user review of drone apps has never been explored. We conducted the largest and most extensive empirical study of UAV mobile apps to-date by analyzing the 1,825 UAV mobile apps across twenty-five categories, with 162,250 reviews (user comments and developers' replies). We categorized the developer replies into seven major categories. We also find that 35% of the developer's replies are associated with providing direct solutions to the drone app user's problems. Whereas, only 1% of the developer replies are related to the app's monetary refund issues.