Ata (may Allah have mercy on him) narrates from Sayyidah Aishah (may Allah be pleased with her): When we travelled to Makkah with the Prophet (peace and blessings be upon him), we used to pray four rak'ahs until we returned.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5423