ATRs start generating money at about 30% load factor.. not much though but you will not be in loss...
Technically wrong, the aircraft is generating money in relation to the route costs. But this is still technically a loss once you consider the costs at base not covered in your aircraft weekly profit. Marketing, staff costs and office rent are all not covering in aircraft weekly operating profits.
Small aircraft are a perfectly good option, utilise them heavily to get the best out of them, they also tend to have no cabin crew keeping staff costs low. Metro 23's can be used to the full extent of their 1000nm+ range if 24 hour scheduled and owned. Best to start with the shorter routes first though, the margins in longer one's are smaller obviously.
A light aircraft would not be suitable for large distances. For instance, it will be almost same cost for you to fly ATR with 25pax demand at 50% load fator as with smaller aircraft that houses 20-30 pax at 80 - 90%.
Be careful with this, I bankrupted an airline trying to make all my Metro routes become ATR-42 routes, you have more expensive pilots, more cabin crew, higher fuel usage, higher insurance, higher landing fees, basically everything get's more expensive.