Originally Posted by
kochleffel
I think of a flag carrier as one chosen to operate certain international routes back in the days when those were strictly controlled, typically with just one airline, designated reciprocally by each of the two countries, to fly the route.
Agreed. That's what they were back in the day, whether or not they were government-owned. PA and TW were the two US "flag carriers" since they "carried the flag" to the rest of the world. Perhaps BN was also considered a flag carrier, with their South American routes, but I don't remember they're ever being referred to as such.