Apparently that one was lifted on by hand, which proved to be more trouble than it was worth. They eventually just made it a permanent attachment and removed the wings so that it could just act as an extra engine for the carrier. The small planes in this photo are Polikarpov I-5s, which weigh about 1,400 kg fully loaded, so 20-ish people could feasibly lift and move one assuming they’ve all got somewhere to stand.