Just a thought, why isn't the 'Weekend View' automatically triggered if you press go flying on the weekend or if you are planning a trip and you enter a weekend date it defaults to the weekend view? Conversely if you actually go flying on a weekday when you planned for a weekend it automatically reverts to the standard view?

There are too many potential issues for us to be comfortable with doing it automatically, although of course we have considered it. Making such decisions on behalf of the user without telling them makes us uncomfortable. There are also potential timezone issues depending upon where in the world you are using SkyDemon.

Could it be, that You did exactly that? Whenever I switch in Flight-Mode, Weekend View is enabled again.

We did, but only if you explicitly set your takeoff time to a weekend. And rather than weekday airspace disappearing altogether (as was the case when this thread was started) it's just faded, like other inactive airspace.