You can fly a pretty good distance in 18min @30-40mph (Napkin Math - somewhere in the 10mile one way range) it would be reasonable to speculate they were within

You can fly a pretty good distance in 18min @30-40mph (Napkin Math - somewhere in the 10mile one way range) it would be reasonable to speculate they were within 10km as they still had a way to go to get across the border but that's still a pretty large area.