This is an app and a home screen widget.
For flight planning this app tells you the current time and the time in zulu for your proposed departure. By running the app or by clicking the widget you bring up the list showing current time in military format, AM/PM format, and zulu time. The list covers 28 hours so you don't have to do the calculation in your head. There is also a slider to quickly see zulutime for the past or future.
The home screen widget that can be sized from as small as practical to as large as practical. Several text styles are available to be compatible with nearly every home screen background. One can easily switch digit themes by tapping the "z" in the upper right corner of the app.
There are no ads and no personal information is connected plus no special permissions are required.