Mus
You mean Bassersdorf to ZRH Airport (Bassersdorf doesn’t have its own airport 😉) and the full fare is 4.60, not 6.40.
The reason for your questions and/or confusion is explained => here:
In the ZVV fare network, there’s no single or 1 zone ticket, the “smallest” one is for 1-2 zones. Therefore you’re basically getting zone 122 for free, and could actually use it if you wanted. (Local zone and short distance tickets are not applicable for your case, as those are only available within the same town / political community)
Zone 110* (Zurich) counts a two zones due to its size and public transport network density. Therefore if traveling from Bassersdorf to Zurich City, you already get a 3 zone ticket for 7.00.
