Hamzah bin Amr Al-Aslami asked the Messenger of Allah about fasting while traveling, and he fasted regularly. So the Messenger of Allah said: 'If you wish then fast, and if you wish then break (the fast).'"  

أَنَّ حَمْزَةَ بْنَ عَمْرٍو الأَسْلَمِيَّ سَأَلَ رَسُولَ اللَّهِ ﷺ عَنِ الصَّوْمِ فِي السَّفَرِ وَكَانَ يَسْرُدُ الصَّوْمَ فَقَالَ رَسُولُ اللَّهِ ﷺ إِنْ شِئْتَ فَصُمْ وَإِنْ شِئْتَ فَأَفْطِرْ قَالَ وَفِي الْبَابِ عَنْ أَنَسِ بْنِ مَالِكٍ وَأَبِي سَعِيدٍ وَعَبْدِ اللَّهِ بْنِ مَسْعُودٍ وَعَبْدِ اللَّهِ بْنِ عَمْرٍو وَأَبِي الدَّرْدَاءِ وَحَمْزَةَ بْنِ عَمْرٍو الأَسْلَمِيِّ  

"We were on a journey with the Messenger of Allah during the month of Ramadan. No one objected to the fast of the one fasting nor the fast breaking of the one who broke his fast."  

كُنَّا نُسَافِرُ مَعَ رَسُولِ اللَّهِ ﷺ فِي رَمَضَانَ فَمَا يَعِيبُ عَلَى الصَّائِمِ صَوْمَهُ وَلاَ عَلَى الْمُفْطِرِ إِفْطَارَهُ  

"We were on a journey with the Messenger of Allah. Some of us were fasting and some of us broke their fast. The one who broke their fast had no objection to the one who fasted, and the one who fasted had no objection to the one who broke his fast. They saw that whoever had the strength to fast then that was good, and whoever was weak, then breaking it was better."  

كُنَّا نُسَافِرُ مَعَ رَسُولِ اللَّهِ ﷺ فَمِنَّا الصَّائِمُ وَمِنَّا الْمُفْطِرُ فَلاَ يَجِدُ الْمُفْطِرُ عَلَى الصَّائِمِ وَلاَ الصَّائِمُ عَلَى الْمُفْطِرِ فَكَانُوا يَرَوْنَ أَنَّهُ مَنْ وَجَدَ قُوَّةً فَصَامَ فَحَسَنٌ وَمَنْ وَجَدَ ضَعْفًا فَأَفْطَرَ فَحَسَنٌ