How are we being matched?

I’m not sure if this has been answered elsewhere, and my apologies if so! But how exactly are we being matched?

This ties into concerns for progression for me. I’m having a great time with the flight overall, but my games are incredibly inconsistent. Sometimes my teammates are highly skilled, other times they are not. There’s no clear sense of how we are advancing, other than cosmetic un-lockables. Hopefully this will be clearer at launch?