Abdullah bin Sawadah al-Qushayri reports from his father, who reports from Anas bin Malik (may Allah be pleased with him), a man of their tribe, that he came to the Prophet (peace and blessings be upon him) in Madinah while the Prophet (peace and blessings be upon him) was having his morning meal. He (peace and blessings be upon him) said: "Come and eat." I said: "O Prophet of Allah! I am fasting." The Prophet (peace and blessings be upon him) said: "Allah has exempted the traveller, the pregnant woman and the nursing woman from fasting, and the traveller from half the prayer."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5486
Tamim al-Dari asked Umar bin al-Khattab (may Allah be pleased with him) about travelling by sea, and he was a great trader by sea; so he ordered him to shorten the prayer, (and said): Allah Almighty says: "It is He who enables you to travel on land and sea." [Surah Yunus: 22]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5487