Funny how we can’t all translate these things. My hubby took flying lessons and laughed at my linear mind. To think of things like the size of the earth and flight paths in theory, is hard for me. I will stick to statistics.
It’s best not to ‘think’ about it, but, rather, ‘do’ something. Next time you’re near a globe, take a piece of string, and stretch it between New York and Singapore. You will actually see the route.
The summer I was 15 I came across a reference to a "great circle route" and "rhumb lines" in a sea story, so I asked my father, a former navigator as a naval and merchant marine officer, what they were. In response, he handed over a massive book, Bodwitch's American Practical Navigator and challenged me to figure it out. After a weekend of close study, I knew what a great circle route and rhumb lines were and had picked up the rudiments of spherical geometry and celestial navigation.
In the process, I also became able to imagine and manipulate a globe and other shapes in my mind, converting simple diagrams from Bodwitch into animations. That has proven useful over the years in not just building and repairing things but also in larger abstractions like understanding Einstein's theory of relativity. I am convinced that any such abilities though were spurred by my father's approach to my original question when I was a teen.
Similarly, your husband probably first dreamed of flying and started reading and thinking about it when he was a boy. For him, flying lessons were a way to realize what he had long imagined, including how to imagine motion in three dimensions.