Well, to tell the truth I had uninstalled the plane but a member of another MSFS forum mentioned that there was an update on 3rd July and so I reinstalled today and now the air spawn is working (as with every other a/c). So whatever was in that update fixed the issue apparently (as a matter of fact the guy in the other forum - which is the official MSFS one) aslo saw his issue, which wasn't quite the same but very close to mine, also resolved.
Anyway I am grateful for your support and appreciate your time in responding.
So thanks again.
Brian