I have been working on a startup idea for the past few years. The prototype is out there and I have a few hundred people using it. My adsense revenue is about as much as I spend on costs. At this point I feel that the only way to take it to the next level is to get some funding and do more agressive advertising (as I'm only going off word-of-mouth at this point)
The only problem is that my target audience is very small. The product is only applicable to people tho fly airplanes. According to wikipedia, thee are 594,285 active certified pilots in the USA. So basically my product has an upper limit of 594,285 users. Even if I were to grow to 100% penetration (which I think is very possible considering my product is very unique and proven to be successfull), are the numbers too small potatoes for investors to give me funding?