It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that when the Prophet (peace and blessings be upon him) left his home, he would pray two rak'ahs at a time until he returned.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12657
Sa'id bin Shufay al-Hamdani (may Allah have mercy on him) narrated: I asked Sayyiduna Ibn Abbas (may Allah be pleased with them both) about the prayer while travelling, and he said: When the Messenger of Allah (peace and blessings be upon him) left his family on a journey, he would pray two rak'ahs until he returned to his family.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12658