Click or tap on the ad to reveal the answer.

How to guess it?
The clues are very small and subtle. I was clement enough to mention the exact year of publishing of this comercial: 1978. Usually, I simply say the decade. 1978. Imagine a major airline that does NOT fly to the cities described. Now, a particularly clever user mentioned the stress on Canada in this advertisement. And he mentioned the exact length of the grey box covering the name of the airline. May I add the ACTA (Association of Canadian Travel Agents) logo in the bottom left corner of the ad?Surprisingly, no one mentioned the lovely clue: the reference to the enRoute credit card! enRoute, which is also the name of this airline's inflight magazine, is a travel and entertainment credit card created by this airline and widely accepted in Canada for several years. However, it was absorbed by Diners Club, itself property of Citibank, in the early 1990s. As of 2001, in Canada, the Diners Club card is called Diners Club/enRoute.
Anyway, my point here is not to praise the Diners Club card, but to reveal one clue that should have been bright for the few people who ever heard of this credit card, outside of Canada! May I add that this airline, as of 2001, has flown or is flying to all of the destinations in this title, except Geneva (or probably under codeshare with Swissair)?