Shaikh Ibn ul-‘Uthaymeen rahimahullah 

Question: Some people take the allowance of combining between prayers on travel. For example between dhuhr and asr. So they combine in advance and they know that they will reach their place of residence before asr prayer. So is this allowed?

Answer:”Yes, this is allowed. However, if he knows or most likely thinks that he will reach before asr time, then what is better is not to combine because there is no need for combining”

[Majmoo’ al-Fatawa (15/422)]

Translated by

Faisal Ibn Abdul Qaadir Ibn Hassan
Abu Sulaymaan