Kouya no Kotobuki Hikoutai Gaiden: Oozora no Harukaze Hikoutai
Genres: Action, Adventure
Type: ONA, Episodes: 12
Aired: Apr 10, 2019 to Feb 29, 2020
Source: Original
Rating: PG-13 - Teens 13 or older
Synopsis:
A short spin-off anime released on "Kouya no Kotobuki Hikoutai: Oozora no Takeoff Girls!" game app and YouTube. 

(Source: AniDB)