Answered by Shaykh Abu Usamah
When in the airplane for eighteen hours or so is one obliged to perform prayer? (Please explain in simpler words) and if they want to make the prayer up. How should they count their prayers? By the place they left or the country that they are to reside in?

Al-Salam `Alaykum
One is definitely required to pray wherever one may be when the salah time enters. The times and number of the salahs that one is required to pray will depend on the location one is flying over at the time. Thus for e.g. if you leave place A at 9 am and after Zawal you are still flying then you will be required to offer Zuhr salah at that time in the airplane. If the salah is not offered Qada will have to be made i.e. it will have to be made up.
The same will apply for all other Salahs.
Allah Ta`ala knows best.
Abu Usama
Durban, South Africa