What problem is the travel planning software startup solving?
Never have I planned a holiday and thought "I need an app for this." Maybe a better flight booking system, or a better guidebook, but never a website or app. In fact, I find planning holidays enjoyable and fairly straightforward.
I know of no-one who has difficulty planning their holiday, beyond the flight problem. And to make this work, you're going to need a lot of people with the same problem, whatever that problem is.
Anyone?