In reality, transfer time in the hub to domestic and international flight is usually different. Transfer to international flight may require additional time for custom clearance and baggage re-drop.
I would like to see something like following in the game world:
transfer time: 00:45 (domestic) 1:00 (international)
Technically, this may introduce a sign/flag to mark if the flight was domestic or international and apply different transfer time there.
If this suggestion has been posted before, then my fault to re-post it and you may ignore it.