 The Sukhoi Su @-@ 35 ( Russian : <unk> Су @-@ 35 ; NATO reporting name : Flanker @-@ E ) is a designation for two separate , heavily upgraded derivatives of the Su @-@ 27 ' Flanker ' jet plane . They are single @-@ seat , twin @-@ engine , <unk> multirole fighters , designed by Sukhoi and built by Komsomolsk @-@ on @-@ Amur Aircraft Production Association ( KnAAPO ) . 
