Yep, the most suitable classification for YSFlight is freeware, not Free Software. It's some old guy's personal project with LLC title that has been running since 1999. I doubt he's making much out of it, as the download page still says the website costs him $50 per month.
Being such an old game it runs on all-custom code he refers to as "YSFlight Kernel" that don't even support texturing, but the game is extremely lightweight and its flight model is at least bearably realistic. That casts contrast to many commercial games like Ace Combat franchises. It also has good keyboard support.
During 2010s the author followed open source movement and dumped some code on GitHub, but the core value of YSFlight remains its easy and compact nature. It's a worthwhile 20MB on your doomsday gaming console to bring to your designated fallout shelter.
Being such an old game it runs on all-custom code he refers to as "YSFlight Kernel" that don't even support texturing, but the game is extremely lightweight and its flight model is at least bearably realistic. That casts contrast to many commercial games like Ace Combat franchises. It also has good keyboard support.
During 2010s the author followed open source movement and dumped some code on GitHub, but the core value of YSFlight remains its easy and compact nature. It's a worthwhile 20MB on your doomsday gaming console to bring to your designated fallout shelter.