Do not condemn one who observes fast, or one who does not observe (in a journey). for the Messenger of Allah ﷺ observed fast in a journey or he did not observe it (too).
لاَ تَعِبْ عَلَى مَنْ صَامَ وَلاَ عَلَى مَنْ أَفْطَرَ قَدْ صَامَ رَسُولُ اللَّهِ ﷺ فِي السَّفَرِ وَأَفْطَرَ