It is narrated from Sayyiduna Ka'b bin Asim al-Ash'ari (may Allah be pleased with him) - and he was one of the people of the ship - he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Fasting while travelling is not righteousness."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16435