Here are a few more details, complete with quotes from legal documents in question...
I've been following this case for some time, and was a little surprised to see it resurface again.
I'm only aware of three, only one of which seems to be approaching Alpha at the moment (Valiance Online). The others are proceeding at some pace--I assume. Ship of Heroes seems to be down the path a bit more than two of the three, which KickStarted before doing a lot of coding. Given the state of the other efforts (what would be the rest of that half-dozen?) it doesn't seem too late to me.
Well, they are working on something as they are still interacting with their community but being very silent about any work being done. The aircraft design goes hand in hand with the vehicle design of DoK.