Frutiger Aero is a design style that was prevalent from the mid-2000s to the early 2010s.
It originated in user interface designs, but later influenced various other media.
It was named in 2017 by Sofia Lee of the Consumer Aesthetics Research Institute, and reemerged in 2023 as a social media aesthetic, becoming popular with Generation Z as an object of nostalgia.
Frutiger Aero art features optimistic themes of technology in harmony with nature and often includes natural imagery, bright colors, and skeuomorphic elements.
Source: Wikipedia
Wondering why we didn't stick with Frutiger Aero?
Designs styles are constantly changing and always will be. If you want to go back to this era, consider installing an OS released at the time such as Windows Vista or Windows 7. It's important to note, however, that these OSes no longer recieve crucial security updates, some apps may not support them any more, and you may encounter other issues.
Given this, it may be worth customizing your OS to look like Frutiger Aero. If you want to do this simply, it may be worth looking at WindowBlinds11. There are also free alternatives which you can try.
Warning: customizing your OS using 3rd party methods may damage your system.