Hi,
that's right: if you click on the Flight-Mode you may start Calengoo. But the good news is that if you don't close it, even if you de-activate back the Flight-Mode, as long as you keep Calengoo running in background, you can swith back to this app and continue to use it. Just open a new app or jump to one still running as needed, and use your smartphone as usual,. At least, this way I can simply thank Dominique and wait until he has cleared the problem with Google.
Kind regards
Michel