Sayyidah Ayshah reported that Sayyidina Hamzah ibn Amr Aslam (RA) asked Allah’s Messenger about fasting during a journey, he being accustomed to fast without interruption. So, Allah’s Messenger (SAW) said, “Fast if you like, or cease to fast if you like”.
[Ahmed16037, Muslim 1121, Abu Dawud 2402, Nisai 2380, Ibn e Majah 1662]