From Halopedia, the Halo wiki
Halo: Starfighter was an internal pitch created by a team within 343 Industries during the early development of Halo Infinite. A playable prototype of the game was created, intending to take the concepts of space combat from the Halo: Reach level Long Night of Solace and expand it into a full game. Halo: Starfighter was inadvertently revealed in a 343 Industries recruitment advertisement in 2018, and concept art created for the prototype was finally released in early 2022 after the launch of Halo Infinite.
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