The calculated distance (air line) between Flawil and Zürich (Kreis 2) is approximately 31 miles respectively 51 kilometers.
By car or train, the actual journey to Zürich (Kreis 2) is certainly longer, as only the direct route (as the crow flies) between Flawil and Zürich (Kreis 2) has been calculated here.
Air line (approximately)
51 kilometers
27 nautical miles