Airplane mode

Bedtime for Android
tm allows you optionally set the airplane mode not to be disturbed while sleeping.
This prevents receiving calls, connections and incoming message notifications.
To turn this feature on and off when Bedtime for Androidtm starts and finishes, you can visit the application Preferences.

About airplane mode

Airplane mode is a mode most modern cell phones can go into in order to cut all communications and radio signals propagated by the phone.
Because it is illegal to use cell phones during a flight and because of the enhanced functionality that Android phones have – it is a way of getting around this restriction. The idea behind airplane mode is that many people wish to continue using their cell phones on planes to do things like listen to music and check appointments, but the use of cell phones on planes is banned due to the fact that their signals could cause interference. Airplane mode allows cell phone users to circumvent the ban, ensuring that their phones are safe to use on aircraft while the plane is in flight; electronic devices must be turned off for takeoff and landing.
In the case of Bedtime for Androidtm this mode is used to prevent receiving any kind of communication.