British Caledonian had an interesting history, as evidence by its lengthy, detailed Wikipedia entry. It had to contend with its giant rival BOAC/British Airways (and by extension, the UK government, both its regulator and major BA shareholder) for route rights; a similar sort of competition can be seen more recently with BMI's ventures in Saudi Arabia and Sierra Leone, Azerbaijan and Asmara. BR itself was absorbed into the BA behemoth in the 1980s.
This handsome graphical first day cover celebrates a Gatwick-Recife service, a DC-10-30 plunging southward in 1977 (curious to know how long this lasted).
This is but one example of how British Caledonian lifted the celebratory first flight cover to new heights of art form and informational presentation. There's no way Timetablist can compete with the substantial and beautifully-presented British Caledonian Tribute site's FCC page, which shows the airline spent 1977 using its new DC-10s to extend to Sao Paulo, Santiago, Houston, Los Angeles, Lagos, and Algiers.