No, but it is good practice to keep your device connected to the internet so that any changes you make to the schedule will sync. The player operates in an offline mode (see below screen shot) but a robust internet connection is still mandatory for content to download successfully.
An intermittent internet connection is not recommended, if a stable connection can not be reached the wifi should be turned off. If you have chosen to operate the APP in an offline mode you should connect to a stable wifi source at least every 7 days and wait for content updates to download before disconnecting the wifi.
You will receive automated reminders to reconnect any devices to the internet if they have been consistently offline for 30 days. If your iPad remains offline for an extended time, the iPad will be locked out and classes will not be available to play.
The below image is an example of an offline device connected to the wrong wifi source. Classes will play for a limited amount of time in this mode. (Virtual classes are showing with a black Virtual logo and no program name)
See the below article on how to avoid your iPad connecting to the wrong wifi source in the future.