an easy and obvious combination of keywords ;-) but what to pick?

I have selected a photo made on board a Lufthansa flight MUC -> FCO, flying over the Alps.
It shows clear BLUE SKY and was taken on... my BIRTHDAY. I was in my very first business trip since March 2020 (prior to COVID, I had flown zillion times ;-) - 155 flights in 2019 alone!)

SKY + BLUE = BIRTHDAY