Exactly. And you wouldn't necessarily maintain the airship there, because those skilled trades might find a better location in Ottawa, Montreal, Winnipeg, or Toronto. So you'd bring those airships back. You might build them here, but they would live their life up north because that's where they do their work.
With regard to time, they will fly roughly 80 miles an hour at cruising speed, so they're not that slow. Of course they could go faster if you want to burn more fuel. It's really a matter of how fast you need to go. But most freight doesn't have to move that fast.