What is the ruling on the fast of one who travels by plane for long distances: should he fast or break his fast and then make it up?

God has linked the permissibility of breaking the fast in Ramadan to illness or travel, and has not differentiated between a traveler on a mount or on foot. The reason for the permission is that travel is likely to involve hardship. If the hardship is absent for a traveler on an airplane, this does not prevent him from benefiting from the concession. So, whoever wishes may break the fast, and whoever wishes may fast. The Prophet (peace be upon him) and his companions used to travel, and some would fast while others would break their fast, without anyone faulting another, provided that fasting did not harm the traveler. For it is not righteousness to fast during travel if it causes harm.