British Airways, British Midland, Easyjet.
There isn't a national airline, however, British Airways could be considered to be the dominant British airline.
British Airways
New England Airlines was created in 1970.
Korean National Airlines was created in 1948.
Korean National Airlines ended in 1962.
Sierra National Airlines was created in 1990.
Morroco Airlines
TAE Greek National Airlines was created in 1951.
TAE Greek National Airlines ended in 1957.
American Airlines I think.
Aeroflot is the national airline for Russia
The national carrier of Singapore is Singapore Airlines.
It depends on where you are travelling FROM.
Singapore Airlines.