Would you be saying that if it was some quip about Canada being cold?

We're talking about a carrier based in a desert nation and a flight that departed said desert nation. It's a joke about the local environmental conditions resulting in the phrase "head in the sand" being potentially ambiguous between the literal meaning and the figurative meaning.

How is this a stereotype?

I live in the Middle-east (the region of the world where Doha is located), trust me, it’s full of sand.

You don’t need to feel insulted for me.