-> The main target passengers of Thai airline are foreigners so that the major rivals of Thai airways are those airlines from middle-east such as Emirate Airlines, Qatar Airways, Etihad Airways.
However, to compete with those rival airlines are quite hard because from oil trading, they have the cost of operating equals to zero. The zero cost makes them has no interest to pay for. On the other hand, Thai airways need to borrow the money to buy a plane. The fraction of plane buying between those rival airlines and Thai airways is 10 planes per 1 plane.
Domestic low-cost airlines, however, are not the main competitor of Thai airways. Because Thai airways services the customers by using 'Full-service program' which is included with all services customers could have, but those low-cost airlines emphasize only on the price of the ticket, the extra services are excluded from the ticket price.