Is already out? I had a problem with the halo 3 flight not getting any message until i posted here so i got it anyway, i’m worried i’m having the same issue with the odst flight 
Being invited to a flight isn’t a guarantee, it can also take some time for the invitation to filter through. Saying that, if you don’t have one by now then it’s very unlikely you have been invited. There is a chance the flight could be extended or that another wave of invites could go out, but no guarantees on that either. As this isn’t really a support issue I’m going to close it off. Keep check on the Halo social channels and here on the Waypoint news section to see if they put out any more unlock waves