When Singapore Airlines gets media for its catering operations, or for its business class product (or first class!) it’s reaching potential customers, sure, but it’s reaching a broader audience that may never fly Singapore Airlines and may never visit Singapore. However it’s projecting the image of Singapore itself as high quality.
A significant amount of public perception of Singapore the country seems to come from Singapore the airline, even among people who have never flown the airline (or who fly it and merely connect through Changi airport).