Because of its scale and technical depth, installing the mod properly is crucial for a stable experience.
Includes everything from Little Birds to A-10 Warthogs.
Note that Project Reality (PR:BF2) has evolved into a completely standalone game that no longer requires a base BF2 installation to play. It can be downloaded directly from the official Project Reality website for free.
Because Battlefield 2's official GameSpy master servers were shut down years ago, community-driven community hubs keep the game alive.