Mindfulness is a word often used, well, mindlessly. But it’s a state that can be described with some precision. The most accepted definition is in Jon Kabat-Zinn’s 1994 book Wherever You Go, There You Are.
And it makes the connection to flying very apparent:
Here’s a good online article with 19 other definitions: https://positivepsychologyprogram.com/what-is-mindfulness-definition/