A note on any “feature” visible in the case study: If it isn’t something that already exists in current-generation AirlineSim, the agency just made something up in most cases to arrive at pretty visuals. While some of those might be useful (like a chart widget or the general idea of an interactive map), other make no sense for the game (like weather data or a widget that shows the two (!) most recent flights. So don’t read too much into those pictures 
Here as well: The main navigation is effectively a dummy and was informed by the content planned for the ASTD. It quickly breaks apart when you think about all the pages AS actually does have, which is why I’ll almost certainly stick with a horizontal navigation + dropdown menus.
I definitely plan on using as much as possible from the design in terms of visuals, but…
…what Pounce2KGaming described was exactly my experience the moment I started implementing the first bits of the design for the ASTD: Lots of whitespace wastes space, complex pages like inventory aren’t accounted for, the “scheduling page” from the case study would maybe be sufficient for a very simple list of things (like an airline or country directory), but that’s about it.
So yeah, there are some nuggets in there that I’ll make use of I can manage it. But at the same time, the overall concept needs a lot more work