Can you outline the app a bit more? I'm struggling to understand the target market. What can the app do exactly? Where was it sourcing its hotels / flights / hire car data etc?
It was meant to be hotels in a single country, it's still operational at http://bookinbulgaria.com In this business, the big competitors all reserve a bunch of rooms in the hotels and manage their booking themselves. The hotel is then not allowed to touch these rooms. The model here was to give the hotels a reception-desk piece of software and have them use it to maintain availability. A lot of the hotels that signed…
For example, holiday home rentals? bed & breakfast? car rentals? I think there is a lot of potential in the car rental market... e.g. allow private vehicle owners to rent out their vehicles. There are probably a few insurance details to work out, otherwise it sounds like you have 80% of that sort of system built already.