Musnad Ahmad 1153:12

Hushaym narrated to us, he said: Yazid ibn Abi Ziyad informed us, from Mujahid, from Aisha, who said: "The riders would pass by us while we were in the state of Ihram with the Messenger of Allah, may Allah bless him and grant him peace. When they drew parallel to us, one of us would let down her jilbab from her head over her face, and when they had passed us, we would uncover it."