Sorry Torres,
I think you will find that Tonga can support its own airline through correct management, and in fact maintain healthy profit.
Even though this may be a small place, domestic flights did have good loadings, and would have been better if Tongas only postal service chose to send mail by plane rather than by boat to the outer islands, and apparently, even the 757 was due to start making the airline some money. This was forecasted by the current growth factor. Tonga had exceed its initial prediction for tourism by a fair margin, and it was only going to get better now that the Pacific Islands seem to be the choice for holiday makers these days.