Question: A fasting person on a plane finds out by glancing at the watch or being informed by phone that it is time to break Sawm (Fast) in the country over which the plane is flying; may they break their Sawm although they can still see the sun because of the altitude of the plane? What is the ruling in case a person breaks Sawm in a given country but when the plane takes off they still can see the sun?
Answer: If a fasting person is on a plane and learns either by checking the time on their watch or being informed by a phone call that it is time in the country over which the plane is flying to break Sawm, but they can still see the sun because of the altitude at which the plane is flying, it is not permissible for them to break Sawm because Allaah (Exalted be He) says: …then complete your Sawm (fast) till the nightfall The time limit (i.e. Nightfall) specified by this Aayah is not met in the case in question, since the sun continues to be seen. However, if a fasting person breaks Sawm in a given country after the setting of the sun, but when the plane takes off they still can see the sun, they should retain their state of having broken Sawm because they fall under the same ruling as the residents of the country from which they took off, where the sun has set while they were there… read more here.