Muhammad bin Ka'b states: On a day about which we were in doubt whether it was part of Ramadan (or not), I visited Sayyiduna Anas bin Malik (may Allah be pleased with him) at the time of Asr, intending to greet him with salam. He sent for food and ate. I said: "Is what you have done a Sunnah?" He replied: "Yes."
(Allamah al-Haythami says:) I say: Al-Tirmidhi recorded a report from him about not fasting when a person intends to travel.
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 4828