Praise be to Allah.
In the Sunnah there are several adhkaar which it is mustahabb for the one who wants to travel to say. These include:
It was narrated from ‘Abd-Allaah ibn ‘Umar (may Allaah be pleased with him) that when the Messenger of Allaah (peace and blessings of Allaah be upon him) mounted his camel to set out on a journey, he would say takbeer three times, then he would say: “Subhaan allathi sakhkhara lana hadha wa ma kunna lahu muqrineen wa inna ila rabbina la munqaliboon. Allaahumma inna nas’aluka fi safarina haadha al-birra wa’l-taqwa wa min al-‘aml ma tarda, Allaahumma hawwin ‘alayna safarana haadha watwi ‘anna bu’dahu. Allaahumma anta al-saahib fi’l-safar wa’l-khaleefah fi’l-ahl. Allaahumma inni a’oodhu bika min wa’tha’ al-safar wa ka’aabat al-manzar wa su’ al-munqalib fi’l-maali wa’l-ahl (Glory be to the One Who has placed this (transport) at our service and we ourselves would not have been capable of that, and to our Lord is our final destiny. O Allaah, we ask You for righteousness and piety in this journey of ours, and we ask You for deeds which please You. O Allaah, facilitate our journey and let us cover its distance quickly. O Allaah, You are the Companion on the journey and the Successor (the One Who guards them in a person’s absence) over the family. O Allaah, I seek refuge with You from the difficulties of travel, from having a change of heart and from being in a bad predicament, and I seek refuge with You from an ill-fated outcome with regard to wealth and family).” And when he returned he would say the same words, with the following addition: “Aayiboona taa’iboona ‘aabidoona li rabbina haamidoon (Returning, repenting, worshipping and praising our Lord).”
Narrated by Muslim (1342).
The phrase “wa ma kunna lahu muqrineen (and we ourselves would not have been capable of that)” means: we would not have been able to subdue it and make use of it, had not Allaah placed it at our service.
“The difficulties of travel” mean hardships; “from having a change of heart” means changes caused by grief and the like: “ill-fated outcome” means, upon one’s return. See Sharh al-Nawawi ‘ala Muslim (9/111).
We do not know whether there is any specific du’aa’ in the Sunnah for protecting a traveller until he returns to his family safe and sound but if the traveller regularly recites the adhkaar for morning and evening, and asks Allaah to keep him safe and sound, and says the du’aa’ for travelling that is quoted above, then we hope that Allaah will answer his prayer and protect him and bring him back safely to his family, unless Allaah wills in His wisdom to test His slave, in which case nothing can put back the decree of Allaah.
What he should remember, when he wants to go out of his house – in order to travel or for any other purpose – and he hopes that Allaah will protect him, is the report narrated from Anas ibn Maalik (may Allaah be pleased with him), according to which the Messenger of Allaah (peace and blessings of Allaah be upon him) said:
“Whoever says – i.e., when he leaves his house - Bismillaah, tawakkaltu ‘ala Allaah, wa laa hawla wa laa quwwata illa Billaah (In the name of Allaah, I put my trust in Allaah and there is no power and no strength except with Allaah)” , it will be said to him: You are taken care of and you are protected and guided, and the devils will move away from him, and one devil says: What can you do with a man who has been guided, taken care of and protected?
Narrated by Abu Dawood (5095) and al-Tirmidhi (3462); classed as saheeh by al-Albaani in Saheeh Abi Dawood.
It says in ‘Awn al-Ma’bood (13/297):
“Then it is said” means, an angel called out to him: O slave of Allaah. “You have been guided” i.e., to the path of truth , “you have been taken care of” means your worries are taken care of.
For some of the du’aa’s that are prescribed in Islam, please see the answer to question no. 12173
And Allaah knows best.