Games like Air Defender
Games like Air Defender include WARNO, Wargame: Red Dragon, Company of Heroes 3, Regiments, and Wargame: Airland Battle. We matched them by the tags players give Air Defender on Steam (Cold War, Strategy, Wargame, Underground, and Real Time Tactics): closest matches first, and among equally close ones the better-known games.

WARNO
Shared: Wargame · Strategy · Cold War

Wargame: Red Dragon
Shared: Strategy · Wargame · Cold War

Company of Heroes 3
Shared: Strategy · Wargame · RTS

Regiments
Shared: Strategy · Wargame · Cold War

Wargame: Airland Battle
Shared: Strategy · Cold War · Wargame

Wargame: European Escalation
Shared: Strategy · Cold War · Wargame

Call to Arms - Gates of Hell: Ostfront
Shared: Strategy · Real Time Tactics · RTS

911 Operator
Shared: Strategy · Simulation · Real Time Tactics

Sea Power : Naval Combat in the Missile Age
Shared: Strategy · Cold War · Real Time Tactics

Broken Arrow
Shared: Strategy · Wargame · Real Time Tactics

Door Kickers
Shared: Strategy · Simulation · Top-Down

Ultimate General: Gettysburg
Shared: Strategy · Wargame · RTS

Master of Command
Shared: Strategy · RTS · Historical

Ultimate General: Civil War
Shared: Wargame · Real Time Tactics · Strategy

Kingdom Heroes 8
Shared: RTS · Real Time Tactics · Strategy

Radio Commander: Vietnam '64
Shared: Wargame · Real Time Tactics · Cold War

Last Train Home
Shared: Strategy · Real Time Tactics · RTS

DEFCON
Shared: Strategy · Cold War · Simulation

NOBUNAGA'S AMBITION: Awakening
Shared: Wargame · Real Time Tactics · Strategy

First Strike
Shared: Strategy · Cold War · RTS

Total War: THREE KINGDOMS
Shared: Strategy · RTS · Historical

Ultimate Epic Battle Simulator 2
Shared: Strategy · Wargame · Simulation

Europa Universalis V
Shared: Strategy · Wargame · Simulation

Creeper World 4
Shared: Wargame · Real Time Tactics · Strategy

