Originally Posted by
Forstbetrieb
Vielfliegerprämie Singular
Vielfliegerprämien Plural
^ correct = prämien here stands for awards
if you are thinking of 'bonus' = 'extra-miles' (due to status or a special promotion) then it is: Vielflieger Bonus Meilen (contrary to Status Meilen)
if it is about 'bonus' = status advantages (like lounge access etc) than it is:
Vielflieger Status Vorteile.