This occurred to me when I was looking at a photo of an A-1 Skyraider.
An online Vietnam air combat game.
Now, North V didn't not have much of an air force, and air to air was limited, but there is a lot of interest in the American presence in the air war. A lot of variety there.
CAS planes like Sandy and Puff the Magic Dragon/Spooky and Spectre, Fairchild AC-119G Shadow
Fast movers like the Phantom, A6 Intruder, A-4 Skyhawk, F-111, A-7 CorsairII, Northrop F-5 Freedom Fighter, Republic F-105 Thunderchief, North American F-100 Super Sabre,
Bombers like the B-52 and Martin B-57 Canberra
Helicopter like the Huey, Chinook, Cobra, Boeing CH-46 Sea Knight,
Cargo planes like the C-130, de Havilland Canada DHC-4 Caribou,
and others A-26B's and C's. OV-10 Bronco, Cessna A-37 Dragonfly
Ground vehicles included:
M41 Walker Bulldog, M48, M60 Patton, M551 Sheridan, and Centurion main battle tank , M113 APC (Armored Personnel Carrier), M50 Ontos, Cadillac Gage V-100 Commando and artillery like the * 75 mm and M102 105 mm Howitzer 60 mm, 81 mm, and 107 mm Mortar, M2 105 mm howitzer, M102 105 mm howitzer, M107 175mm self-propelled, M109 155 self-propelled howitzer, M110 8-inch self-propelled howitzer
PAVN equipment included:
82 mm and 120 mm mortars (M1938), 107 mm, 122 mm, 140 mm rockets
MiG-21s jet fighter
MiG-19s jet fighter
MiG-17s jet
AN-2 aircraft
Mi-8 helicopter
PT-76 amphibious tank
BTR-50
BMP-1
ZSU-23-4 anti-aircraft self-propelled systems
T54-55 main battle tanks
ZSU-57-2 anti-aircraft self-propelled system, fielded in limited numbers.
And scores of AA and AAA and SAMs, and lots and lots of soldiers to send forward as cannon-fodder.
You have several major areas to contend with. North Vietnam Air war. South Vietnam (with delta, highlands, and jungles), Carrier Group on station, and the Ho Chi Minh trail and "secret" war in Laos. You've got day as well as night time for operations.
You have a big map representing the AO. Cities, Bases and Firebases scattered about. PAVN/NVA Armies could be moved like Task Groups are in AHII.... take command and move them where you want to take over. They get near a base or other strong-point they begin a siege. American side has a couple of it's own TG "Armies" (but far fewer) and most troop movement by air.
Ho Chi Minh trail supplies armies in the south. Endless ant trail. The more it's attacked, the weaker the PAVN and NVA forces in the south, the more ant-trail supplies move forward, the stronger those Armies get. Triple canopy would make locating them very hard to do.
Conversely, American and S V forces must be supplied by air to maintain their strength at strong points/bases against siege. To take an object requires the airlift of enough troops and supplies to an area.
Siege becomes an attrition event. If American forces unable to attack the PAVN/NVA forces or resupply the strong point with supplies and fresh troops --- it falls. If PAVN/NVA forces not able to move enough supplies down the Trail, they fail to overwhelm the attackers.
Missions posted for pilots.
When an American Pilot gets shot down, it can at times generate a S&R mission to recover that downed pilot. (downed pilot not stuck there, a bot takes his place). Pilots can respond to that. At the same time "enemy activity" (bots) increases in the area, and PAVN players know there is a pilot in that area, and can man local anti-air defense.
A sieged base would flash, and there would be calls for CAS, napalm runs, bombing attacks, arc-light, resupply of equipment and troops, medivac, and so forth.
Random medivac and CAS request missions,
Up North, it would be PAVN interceptors and air defense vs American bombing attacks. Players can take command of any SAM, AA, or AAA site. Around siege strongholds, players on both side can take charge or arty and mortar fire and GV's as appropriate.
Granted, this puts much more emphasis on the American side of the War than the N V side for player participation. This game also depends on much more AI code support than AHII does. Using the equipment of the era, and tactics, it may be possible to create a fictional battleground similar to this for a generic war arena, with a 3-way fight as well.
Just some rough thoughts.
Running a Huey on a mission to a hot LZ. Flying Skyraiders on a CAS mission. Operating Spooky or Spectre over a sieged base or hunting over the Ho Chi Minh trail. Dropping a LRRP team near the trail to gain better intel on an area for the team. Air dropping cargo over Laos. Running a river boat in the delta.
Good times. Fun times.