Due to historical reason, I have a membership on Air Canada Aeroplan and I have 1238 miles inside, which is expiring August 2020. Early last year, due to rumour that Aeroplan would discontinue to be a *A FF programme, I signed up for another programme A3 and credited 3826 miles into it, which never expires. There is little chance that I will take AC in the future because I'm not planning to visit North America anymore, and nearly all my future travel will be between Asia and Europe.

Now Air Canada has announced that it will honour the existing Aeroplan miles 1-to-1 upon launching its new programme in 2020, which gives confidence to continue accumulating miles.

*A is my least travelled alliance among the three, because TK does not offer competitive fare between Asia and Eastern Europe compared to SU, and the modification of HKG-ARN route to HKG-CPH means I will no longer consider SK for travel to Sweden, but SU or AY instead (I generally takes the most direct route as shown on gcmap - if the number of transfers is the same, equivalent to least total flight time (excluding transfer)).

My aim is to get enough miles to burn them in form of a single-journey one-way short-haul flight, either within greater China region or within Europe.

I'm taking TK again this July because I'm travelling Helsinki - Istanbul - Hong Kong, requiring a direct flight from Helsinki - Istanbul, so there is no other viable choice apart from buying a TK HEL-HKG one-way fare with stopover, and I am taking class L, which gives 50% on A3, and 70% on AC. By crediting the flights on AC the expiry date is extended for 3 years to 2022, but I am not sure if I will still take any *A flights afterwards before 2022, while if I credit to A3 which never expires, I'm letting the AC miles expire in 2020.

Which one do you suggest for me? A3 or AC?