Ibn Majah

Benefit:
From this it is understood that if the Sunnah prayers of Fajr are missed, they can be performed even after the sun has risen.
However, they are then considered as being made up (qada).
Therefore, it is better to perform them before sunrise, because they are a part of the Fajr prayer itself.
If they are performed within the time of Fajr, then they are not considered as qada.

Hadith Commentary: Benefits and Issues:

➊ If the prayer is missed collectively, then as soon as the opportunity arises, arrangements should be made for it. The adhan should be called and the sunnah prayers should be performed. Then, the congregation should be established by calling the iqamah.

If more than one prayer has been missed, then for the first prayer both adhan and iqamah are to be given. For the subsequent prayers, there is a choice: either give adhan and iqamah for each, or suffice with only the iqamah.

Imam Abu Hanifah rahimahullah and Imam Ahmad rahimahullah are of the opinion that adhan should be given for every prayer. Imam Malik rahimahullah and Imam Shafi'i rahimahullah, in their final opinion, do not consider adhan necessary for the subsequent prayers.

➋ According to Imam Malik rahimahullah, Imam Shafi'i rahimahullah, and Imam Ahmad rahimahullah, it is better to make up (qada) the sunnah prayers. Whether the sunnah prayers were missed along with the obligatory (fard) prayers or only the sunnah prayers remain, and according to the Hanafis, if only the sunnah prayers remain, then their qada is not to be performed. Qada is only for the obligatory prayers.

1:
Perform the prayer (salat) for My remembrance (Taha: 14)