Vassal is a Java-based program that allows you to play Fighting Wings online / PBEM with your friends. To use that, you need a minimum of 2 things, the Vassal Game Engine and the Gamebox, plus optionally a saved game for starting new games.
The "Official" Vassal Fighting Wings Gamebox and Extensions are available at Ian Wedge's page
I made a couple of Vassal Extensions to help me play the PBEM ames :
Extended Sky Map (2.16 KB) (11/03/2012). The regular sky map in Vassal has 54 rows and 53 columns. This one has 154 rows and 98 columns.
Extended Sky Map 2 (2.20 KB) (11/04/2012). The regular sky map in Vassal has 54 rows and 53 columns. This one has 154 rows and 177 columns, and is numbered from hex 0001 instead of hex 1001.
Achtung Spitfire Ground Map (14.7 MB) (11/03/2012).
Buffalo Wings Ground Map (16.1 MB) (11/03/2012).
Over the Reich Ground Map (11.8 MB) (11/03/2012).
Battleaxe Campaign Map (6.4 MB) (11/03/2012).
Battle of Britain Campaign Map (4,7 MB) (11/03/2012).
Darwin Campaign Map (2.38 MB) (18/05/2013)
8 AF Map (3,23 MB) (05/09/2018)
Operational Mission Track (1.33 MB) (11/03/2012).
Personal Operational Mission Track (6.49 MB) (02/03/2013)
Tactical Maneuvering Grid (844 KB) (11/03/2012).
Extra German counters, with sub optimal resolution (259 KB) (19/08/2011)
2 Mediterranean Front Desert camouflaged Bf109E from Ian Wedge old Desert extension
1 Eastern Front Fw89 from JD's "Whack the Piñata" double blind game, that Ian Wedge had put into a "special.zip" extension.
1 Western Front Do17 counter.
3 Ju87 counters, 1 Western Front, 1 Eastern Front and 1 Mediterranean Front.
Extra Japanese counters, with sub optimal resolution (59.4 KB) (19/08/2011)
2 B5N Kate counters, 1 from the Akagi, 1 from the Shokaku.
Polish counters, with sub optimal resolution (70.1 KB) (19/08/2011)
1 PZL P.11c counter
1 PZL P.23b counter
Extra USA counters, with sub optimal resolution (122 KB) (19/08/2011)
OS2U Kingfisher counter for my "A Daring Encounter" game.
F4U-1 variation to the F4U-4 counter (only changed the name on the base in the new counter).
Land Units counters (844 KB) (18/05/2013)
BW, AS, OtR and WD land units, but not all of them.
Markers
Ships (2.15 MB) (03/03/2013)
All ships from WD, and those from AS and OtR
OMT Markers (595 KB) (18/05/2013)
Border, Formations, Airbases, Targets, Weather, etc...
Reg's extra British counters (29/09/2013)
Defiant
Fulmar
Mosquito
Wellington
Blenheim I
Hurricane IIB Desert Air Force
Tempest II
Battle
Whirlwind
Blenheim IV
Reg's extra German counters (11/03/2013)
Do17Z
Ju87B
Ju88A
Do335
Reg's extra Japanese counters (04/10/2013)
A5M2 Claude
A5M4 Claude
A6M2 Zero (white, dottled, green)
A6M3 model 32 Zero (white, dottled, green)
A6M3 model 22 Zero (white, dottled, green)
A6M3 model 22a Zero (white, dottled, green)
N1K2-J George
Reg's extra Soviet counters (21/10/2012)
Il-2
Reg's extra USA counters (11/03/2013)
Spitfire V (Eagle Squadrons)
Reg's extra RAAF counters (23/09/2013)
Spitfire VC Trop (1 RAAF Fighter Wing)
Adding an Extension to Vassal.
The extension file should not be unzipped or decompressed in any way. It should stay as you download it, and you can use the .vmdk file extension to avoid confusing it with a zip file.
In the end the extension file will be placed in a subfolder named exactly like the module you use for Fighting Wings with the "_ext" suffix added.
For example, if the Vassal module you use for Fighting Wings is named "FW v1.vmod" and is in the "C:\Program Files (x86)\VASSAL\Fighting Wings" folder, then the extension "Dud.vmdx" will be placed in the "C:\Program Files (x86)\VASSAL\Fighting Wings\FW v1_ext" folder.
When Vassal is loaded, the extension maps will appear as an extra button in the top tool bar, and when you click on the button, the extension map will appear in a new window.