if Im on the plane at fajr time but its not possible for me to pray standing up at all. And by the time I arrive to the other country its already duha time. When should I pray? When we arrive or on the plane sitting down? And do we follow the time of our previous country to pray or the next country?

Ustadh AbdulAziz al-Haqqan

On the plane to the best of your ability and u follow the time of where you are at the moment of praying.