Not a teacher.
"Those who live for the sky" seems better, but I think that applies to pilots more than air traffic controllers. Maybe "those who live for the stress and boredom of sitting on the ground while the pilots play" is better. (I'm a pilot, so I'm biased. )
"The traffic cops of the sky"
"The guardians of the sky" <-Probably the most positive
"Masters of the sky"
What are you looking for? Something that speaks of air traffic controllers' love of the sky, their responsibility, their control, their professionalism, their passion? Many things can be said of American air traffic controllers (mostly good! ), and I assume yours are similar.