[mrhektor]

One of the most important things I learned while being in a somewhat similar position as you a little while ago, is to stop concentrating on sales at this juncture, and concentrate on the product instead.

As a solo-cofounder, your focus will keep shifting from sales to engineering, and it's very very hard to do both. I recommend stopping all new sales, align your entire company on stabilizing the product, and your existing customers will become your sales team.

As others have said, it would be helpful to take a break with your team, craft a new product-focussed strategy, and make deadlines for delivery.

Lastly, remember that you've actually achieved a lot (getting paid pilots is hard as a startup). Even if you do quit (I recommend giving it some more time though), I think you have learned what NOT to do in your next venture. Good luck!