There appears to be a missing routine, dfbifs.m, not included in the zip file....it computes feedback gains:
[u,xs,K,uf]=dfbifs(A,B,C,Q,R,Qo,Co,yo,Qf,Cf,yf,N,y);
Also, autoland.m is not referenced in the text.
Overall, the text appears to be very complete in discussion of autopilot design...the text is terse but excellent in scope and detailed designs. A second edition with simulink files would be a welcome addition.