بسم الله الرحمن الرحيم
Qadais similar to ada (in performing), so as much salah you have missed during a journey offer them and offer them with qasr i.e. pray the salah of four rakah only two rakah. There is no qaza of sunnah salah. Yes, there is qadha of witr salah.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.