Well, basically u need to know what kind of market you are going to going to serve.
First the routes: either short/very short haul routes with high frq services., or more long-haul services.
Then there is theissue about target marketHigh-Fare Business class pax or the Y-Class public or Charter type, which will determine your revenue structure.
Both have their own adv. as well as disadv. A model based on the Y-Class traffic would be more susceptible to attrition by rival carriers.
You also have to determine the level of service u want to offer, which adds to the cost.
The most difficult thing that i have encountered is to sell tickets. That is going to be very difficult. So u basically have to set up a network to sell your tickets.
All this is much more important than money. That is definitely there, but i would say that your first priority should be to network yourself with the Travel industry well and understand the economics of how the whole thing works. And this network of contacts should help you tom. to sell u'r tickets.
About money: there are quite a few organisations out there willing to put money on good ideas. In the US esp. there should be many more of these firms. So concentrate on developing a good business plan.
One last thing: Dont get into this JUST b'cos you love planes, and u want a few Airbuses/Boeings with Herman written across the fuselage. If this is about an ego trip, drop it right now. U;ll save yourself a lot of money.
Get into it only if you have a solid business plan.