I'm afraid he's right.  I have been given planes in much better shape just to clear someone else's clutter.  If you found someone who still flies control-line the box of tin tanks may interest them.  I don't know anyone locally still flying that way.

The "Tiger" trainer doesn't look too bad off.

Problem with the other wrecks is that most folks with the skill to rebuild them have a few of their own in the corners waiting for fix-up . . . that we never seem to get around to.

Don't know anything about helicopters - couldn't say if that has value or not.  If it's like an airplane the airframe is worth the least when compared to engine and electronics (receiver/servos/battery).  And the trouble with kits is you never know if the builder knew what he was doing.  The trouble with ARFs and engines is they could have been abused or just well used and tired or worn out.