Obviously, shortening an international flight provides the highest value for your first major route. How well can this scale down to domestic flights? Turning a 3-4 hour flight into a 60-90 minute flight, or a 90 minute flight into a 30 minute flight, appeals quite a bit.

EDIT: your answer at https://news.ycombinator.com/item?id=11330935 applies here.

Do you have concrete plans to change those regulations? Do you have solutions for the problems addressed by those regulations (e.g. noise)? Will this scale down well if you have to reach a certain altitude first?