Travel with Apple Watch

One of my ways of coping with jet lag when traveling is to change to my destination time zone as soon as possible. I normally do this after boarding my flight. But - my Apple Watch insists on taking its time zone from my phone (ok), and does not allow changing said time zone once the phone is off/in flight mode (not so ok). Apart from using the world clock app (an awkward workaround), is there a way to set the time zone when phone and watch are in flight mode?