The traveller praying two rakahs if he wishes and four if he wishes

Sayyidah Aishah (may Allah be pleased with her) said that the Prophet (peace and blessings be upon him), while travelling, would sometimes shorten the prayer and sometimes pray it in full, sometimes fast and sometimes not fast; he would delay Zuhr and hasten Asr, and delay Maghrib and hasten Isha.

Abu Qilabah said: If you pray two rak'ahs while travelling, that is the Sunnah, and if you pray four, that too is the Sunnah.

Sayyidah Aishah (may Allah be pleased with her) used to pray the full prayer while travelling.

Abu Najih al-Makki said: The Companions of the Prophet (peace and blessings be upon him) used to travel together; some of them would pray in full and some would shorten, some would fast and some would not fast. Despite this, no one would find fault with anyone else.

Bistam bin Muslim said: I asked Ata about shortening the prayer while travelling, and he said: If you shorten, it is a concession, and if you wish, pray it in full.

Maymun bin Mihran asked Sa'id bin al-Musayyib about the prayer while travelling, and he said: If you wish, pray two rak'ahs, and if you wish, pray four rak'ahs.