SDL Sopwith

Screenshot, Windows 7
SDL Sopwith running under Windows 7 (screenshot credit: Alaux)

Screenshot, Linux XFCE
SDL Sopwith running under Linux with the XFCE desktop.

Screenshot, macOS
SDL Sopwith running under macOS.

Screenshot, Haiku
SDL Sopwith’s use of the SDL library means that it will even run on more niche OSes such as Haiku.

Screenshot, NetBSD
Looks can sometimes be deceptive. This is actually SDL Sopwith running under NetBSD on a Raspberry Pi. In the screenshot you can see a splatted bird that has wounded the plane, two optional features that can be turned on.

Screenshot, multiplayer
Multiplayer mode allows you to dogfight with your friends.