Often, airlines are unable to sell all the seats of a flight and some seats go unsold. So, with what occupancy ratio is it usually profitable for an airline to operate?
For example, Recently, a Turkish Airlines A330, flying from Bangkok to Istanbul (12,000 KM) made an emergency landing after a bomb hoax. The interesting thing was that it was carrying only 142 passengers, against its marked capacity of 250 passengers (occupancy ratio of about 0.6).
And what are the factors which would influence this choice – like probably, it would be cheaper to operate a B787 with 0.6 occupancy ratio compared to a B747. What are some other factors which influence this?