Marine Air Virtual is a VA where folks can fly either military or civilian aircraft, from any nation, although the team prefers USMC/Navy aircraft to be operated on planned group operations.
The team offers achievements, which you’ll probably get from flying their routes and missions, which, according to the organization, are being added frequently.
To join then, you won’t need to go through check rides and neither IVAO nor VATSIM are required. JoinFS is required, though and you should also join their Discord server. This means that any JoinFS-compatible sim will work.
You can learn more about the Marine Air Virtual on their Discord server or on their Facebook page.
