Maybe someone with a better memory can be more specific.
I guess that would be me. This is a long and complicated story, and I will try my best to be as succint and as factual as possible.
Singapore and Canada signed their first bilateral in the mid-80s, and AC
not long after. During the negotiations, the Civil Aviation Authority of Singapore (CAAS) was primarily interested in getting AC
, and hence they agreed to terms that were not favourable to SQ
starting services to both YVR
. For example, to YYZ
could not operate through a number of European cities, and all flights had to stop first in Montreal. To YVR
, they could not fly through some Asian cities, and they had to stop on the US West Coast first.
protested to the CAAS, and around 1986 or so they gave Canada 12 months' notification that the bilateral was being voided. The two countries went back to the negotiating table and agreed on a new bilateral. With this new bilateral, SQ
in 1988 and SIN
in 1991. AC
, meanwhile, withdrew their route in early 1991 because of losses.
Not long after SQ
started flying to YYZ
protested to Transport Canada, saying that SQ
flew too many fifth freedom passengers between Europe and YYZ
. Incidentally, AC
did not fly to AMS
at the time but they had nonstop service to VIE
. Transport Canada therefore gave 12 months' notice. This time, the two countries could not agree and the bilateral was cancelled.
continued operating the YVR
service under a "special license" that has to be renewed yearly. The YYZ
flights were discontinued. Till today, the two countries do not have a bilateral.
There is more to this than what I have described above, but this is the gist of it