Generation

Generations are categories that separate major technological leaps in the development of fighter aircraft propelled by jet engines. Multiple definitions have been proposed; no standardized definition has been accepted by the aerospace industry as a whole. Aerospace companies use generations as marketing terms to present their fighter aircraft as superior to their competitors, which they claim are within a lower generation.

The Ace Combat franchise rarely addresses fighter generations since aircraft tend to have similar gameplay features. Most generation definitions are provided in materials outside of the games. In gameplay, generations were made more apparent in Ace Combat Infinity and Ace Combat 7: Skies Unknown through the Aircraft Tree, where aircraft further to the right on the trees are usually in higher generations.

Definitions
In Ace Combat Infinity, leveling up the MiG-35D Super Fulcrum to Lv.3 unlocked the "Fourth Generation ++" nickname, which follows the definitions laid out in Air Force Magazine in October 2009. At the same time, the ADFX-01 Morgan's description in Infinity stated it was a "4.5th generation" aircraft, which follows the definitions laid out by Aerospaceweb.org.

A combined set of definitions is available below, following Aerospaceweb's naming scheme.
 * 1.
 * 2. Radar and
 * 3., s, and multipurpose combat roles
 * Examples: F-104C Starfighter, MiG-21bis Fishbed, J35J Draken, F-4E Phantom II
 * 4. High maneuverability and sophisticated avionics
 * Examples: F-14A Tomcat, F-15C Eagle, F-16C Fighting Falcon, Mirage 2000, MiG-29A Fulcrum, Su-27 Flanker-B, Tornado GR.4
 * 4.5. Reduced, advanced avionics (potentially including ), and potentially minor stealth
 * Examples: Typhoon, Rafale M, F/A-18F Super Hornet, Su-35S Flanker-E
 * 5. All-aspect stealth with internal weapons bays and integrated avionics for total battlefield data
 * Examples: F-22A Raptor, F-35C Lightning II, Su-57, YF-23 Black Widow II

The sixth generation of fighter aircraft is still only conceptual in real life, but at least one fictional aircraft in Ace Combat—the ADF-11F Raven—has already been described as seventh-generation. Not all fictional aircraft are as cutting-edge; as stated above, the ADFX-01 Morgan is officially considered in the 4.5th generation. The X-02 Wyvern is officially considered to be a fifth-generation aircraft.