Believe it or not, the numbers are starting to flatline/possibly increase again. If hitech was intrigued I think it wouldn't take much for us, as a community to pay for some advertising. I would pitch in 100$ TO THAT EFFORT.
To be honest, and its purely anecdotal, I have seen so many over the years who found this game from a TV commercial. IMO, that's the most effective marketing today because people can look up the game on their phone right there on the couch and don't feel like they are being tracked by an Ad on the internet.
I see these cheesy phone game commercials all of the time where they hire Arnold Schwarzenegger to promote it. It works.
Also, I believe the pictures and videos tab on the website should be updated. I tried to show a colleague the game the other day. Wanted to show him a corsair. Could not find it on the pictures tab. Would be nice to have 1 pic atleast of all of the planes. Also would be cool to have more approved videos uploaded to the videos tab. Not all new comers to the website will know there is a films a screenshot section in the forums. IMO this really helps because it allows the person to see the game from a positive perspective and could definitely encourage them to download it.