I heard the Messenger of Allah ﷺ say, "It is not righteousness to fast while traveling."
أخبرنا إسحق بن إبراهيم قال أنبأنا سفيان عن الزهري عن صفوان بن عبد الله عن أم الدرداء
سمعت رسول الله ﷺ يقول ليس من البر الصيام في السفر
[Sahih] Ibn Majah reported it in the Book of Fasting, chapter on breaking the fast while traveling, hadith no. 1664, from the hadith of Sufyan bin Uyayna, with this chain. It is also found in Kubra, hadith no. 2563. Hakim graded it sahih (1/433), as did Dhahabi. It has many corroborating narrations, see the hadith that follows, no. 2259.