Just asking, is the flight gonna be on console?
Yes, both Series, and One
Yes the flight will be on the entire Xbox One family of consoles and the next gen Series S and X.
it will be on Xbox One, Series X/S and PC (steam). you will get a notification in halo waypoint (possible email too) with a code for steam or Xbox store.
With the Xbox store I’m not 100% on how you will get the game as i’ve never been apart of an halo flight on Xbox but I assume it will be like on PC (redeem a code) or maybe its automatically added to your account but that’s just a guess.