Very cool UX!! App looks great and user interaction is fantastic! Got a try-out coupon at Websummit 2018. Regarding taking sleep during a flight I think it is impossible to sleep in the first and last hour, so suggest to modify the algoritm for this. Also I expected to have some food advice, in my experience it enhanced my adoption to the new timezone when I modify the times and amounts of food I take. The payment schedule looks expensive to me. I would be willing to pay EUR 5 for a next (single time) use. All the best with your further developments!