Prayer times on a plane

I will be flying from the West (NYC-7hours in flight) after isha going towards the East(Pakistan-8hours in flight) with one stop in Manchester England for about 2 hours .How do I culcuate the time of the prayer while I am in flight .

Walaikum assalam wa rahmatullahi wa barakatuh,

I pray this finds you in the best of health and spirits.

One would make a reasoned estimate, relative to one's place and position. [ Ibn Abidin, Radd al-Muhtar; Tahtawi/Shurunbulali, Hashiyat Maraqi al-Falah ]

Maghrib is easy: it is when the run has gone below the horizon. Isha is when it is now totally dark. Fajr is when light has appeared on the horizon. Zuhr time doesn't very much from place to place. Asr is when shadows of things begin to extend themselves--and to be safe, pray it after half-way between Zuhr and Maghrib.

And Allah alone gives success.

Faraz Rabbani