Hadith 4:138
Yazid ibn Harun narrated to us, from Asim, from al-Hasan, that he said: There is no harm in traveling during Ramadan, and he may break his fast if he wishes.
حدثنا يزيد بن هارون عن عاصم عن الحسن أنه قال لا بأس بالسفر في رمضان ويفطر ان شاء