Mishkat al-Masabih 2690
‘A’isha said:
Riders would pass us when we were performing the rites of pilgrimage along with God’s messenger, and when they came by us one of us would let down her outer garment from her head over her face, and when they had passed on we would uncover our faces. 

Abu Dawud transmitted it, and Ibn Majah has something to the same effect.
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: كَانَ الرُّكْبَانُ يَمُرُّونَ بِنَا وَنَحْنُ مَعَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مُحْرِمَاتٌ فَإِذَا جَاوَزُوا بِنَا سَدَلَتْ إِحْدَانَا جِلْبَابَهَا مِنْ رَأْسِهَا عَلَى وجهِها فإِذا جاوزونا كشفناهُ. رَوَاهُ أَبُو دَاوُد وَلابْن مَاجَه مَعْنَاهُ