I don't have much time for people who go around telling everybody what they're going to do. I prefer those who can tell you what they have accomplished. Tommorrow's promises will not pay for today's groceries.
So my advice to young Martin Halstead, get your aircraft airborne and then tell everyone about it (once you have decided on a route, that is!). Most passengers will want to wait and see that you can afford to fly the route empty before risking their hard earned cash on your startup. The ability to fly empty for three months, also known as 'building the route', should be covered by your startup fund. If you cannot afford to fly empty for at least three months, don't even bother going any further. The only time you don't need it is when you are taking over a mature route. The last time that happened was when Eastern went on the HUY-ABZ route, which was abandoned by KLM.
Starting an airline with no prior experience will prove extremely difficult and the public doesn't need (or want) a blow by blow account about every setback you suffer. You realised that the PA-31 is a non starter, soon you will realise that the J-31 is no different, just a 'J' instead of a 'PA'. These aircraft are all museum pieces. To provide low fares, you need a modern turboprop. The J31 isn't one, which is why you won't see £49 fares on Eastern !
Richard Branson wasn't 19 when he started Virgin Atlantic, so I guess you have a a few more years to learn this trade properly !
CG