The Osean Air Defense Force was first known to have been deployed in 1995, during the Belkan War. Following Belka's expansion into neighboring territory on March 25, the Osean military formed an alliance with the Republic of Ustio and created the Allied Forces along with Yuktobania and Sapin. The OADF would participate in various operations throughout the war, most notably Operations Battle-Axe and Cannibal. Following the war, the OADF would recruit a number of Belkan pilots into their ranks.
In 2010, the OADF would once again see action during the Circum-Pacific War. The Air Force played an important role throughout the war, defending the Osean Federation from the initial attacks and later participating in the invasion of Yuktobania. In particular, the Wardog Squadron became a major source for Osean Army's morale, gaining a reputation as the "Demons of Razgriz" following Operation Long Harpoon where they sank the Yuktobanian underwater submarine, Hrimfaxi, in the Razgriz Straits.
In 2019, the Kingdom of Erusea declared war on the Osean Federation and once again, the OADF was deployed. During the Lighthouse War, the force would be deployed during various operations, the extent of which is currently unknown.
The Osean Air Defense Force follows a traditional air force structure. It is divided into large groups, wings, which are divided into smaller groups, squadrons. The OADF is under the jurisdiction of the "Air Combat Commando" group, while the body responsible for commanding the force itself are the Osean Air Defense Force Central Command. The OADF also features smaller sub-divisions, including a Technology Development Bureau.
- Alpha Squadron
- Delta Squadron
- Halo Squadron
- Omega Squadron
- Rapier Squadron
- Viking Squadron
- Aircraft: B-52H Stratofortress x5
- Viper Squadron 
- Wardog Squadron
- Aircraft: F-14A Tomcat x4
- The formation changes with the player's choice.
- Aircraft: F-14A Tomcat x4
- Wizard Squadron
- Sorcerer Squadron
- Aircraft: F-15S/MTD x8
- Mage Squadron
- Gargoyle Squadron
- Golem Squadron
- Skeleton Squadron
- 502nd Tactical Fighter Wing
- Cyclops Squadron
- Spare Squadron
- Strider Squadron
- Salamander Squadron
The Osean Air Defense Force has employed a wide variety of aircraft, ranging from ground assault aircraft to state-of-the-art fighters, such as the YF-23A Black Widow II.
- F-4E Phantom II
- F-4G Phantom II Wild Weasel
- F-4X Phantom II
- F-5E Tiger II
- F-20A Tigershark
- F-14A Tomcat (Owned by the Osean Maritime Defense Force.)
- F-14B Bombcat (Owned by the Osean Maritime Defense Force.)
- F-14D Super Tomcat (Owned by the Osean Maritime Defense Force.)
- F-15C Eagle
- F-15E Strike Eagle
- F-16C Fighting Falcon
- F-16C Block 60
- F-2A Viper Zero
- F/A-18C Hornet (Owned by the Osean Maritime Defense Force.)
- F/A-18E Super Hornet (Owned by the Osean Maritime Defense Force.)
- F/A-18F Super Hornet
- EA-18G Growler (Owned by the Osean Maritime Defense Force.)
- F-22A Raptor
- FB-22 Strike Raptor
- YF-23A Black Widow II
- F-35C Lightning II (Owned by the Osean Maritime Defense Force.)
- F-117A Nighthawk
- A-6E Intruder (Owned by the Osean Maritime Defense Force.)
- EA-6B Prowler (Owned by the Osean Maritime Defense Force.)
- A-10A Thunderbolt II
- YA-10B Thunderbolt II
- Tornado GR.1
- Tornado GR.4
- Tornado F3
- Tornado ECR
- EF-2000 Typhoon
- Mirage 2000C
- Mirage 2000D
- Rafale B
- Rafale M (Owned by the Osean Maritime Defense Force.)
- MiG-21bis Fishbed
- MiG-21-93 Fishbed
- MiG-29A Fulcrum
- MiG-31 Foxhound
- MiG-31M Foxhound
- MiG-1.44 Flatpack
- Su-27 Flanker
- Su-32 Strike Flanker
- Su-33 Flanker-D
- Su-35 Super Flanker
- Su-37 Terminator
- Su-47 Berkut
- X-02 Wyvern
- ADF-01 Falken
- ADFX-01 Morgan
- In the European release of Ace Combat 5: The Unsung War, the name of the OADF is changed to "Osean Air Defence Force", following British spelling conventions.
- The Osean Air Defense Force (as portrayed in AC5) is based on the real-world United States Air Force (USAF), bearing distinctly similar service dress uniforms, flight suits, aircraft, rank structure, and organizational structure (albeit outdated; the USAF stopped using the Air Division command level in 1992). However it should be noted that in the USAF, Airman First Class is an enlisted rank and in the USAF enlisted personnel cannot serve as pilots or undergo flight training.
- ↑ 1.0 1.1 Ace Combat 5: The Unsung War
- ↑ Ace Combat Zero: The Belkan War
- ↑ 3.0 3.1 Ace Combat 7: Skies Unknown
- ↑ "A Record of The Belkan War". Cutscene. Ace Combat Zero: The Belkan War.
- ↑ Mayhem, Ace Combat Zero: The Belkan War
- ↑ The Inferno, Ace Combat Zero: The Belkan War
- ↑ Cutscene 16, Ace Combat 5: The Unsung War.
- ↑ Rendezvous, Ace Combat 5: The Unsung War
- ↑ Demons of Razgriz, Ace Combat 5: The Unsung War
- ↑ Ace Combat 7 Skies Unknown - E3 2017 Trailer
- ↑ Ace Combat Zero: The Belkan War - Assault Records #004.
- ↑ ACES, Ace Combat 5: The Unsung War.