Abd al-Rahman bin Ka'b bin Malik (may Allah have mercy on him) narrates from his father (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) seldom set out on a journey, whether for jihad or otherwise, except on Thursday.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10307