There are 4 total Shinden parts hidden in adventure mode. To get these parts, you have to find the alternate landing strips and land there. As with the Swordfish wing, you can find the strips more easily if you first unlock the Special Radar in target mode.

Fuselage: The Towers Of Terror alternate landing strip.
Jet Engine: The Great Divide level alternate landing strip.
Right Wing: The Adventure Begins level alternate landing strip.
Left Wing: The Labyrinth level alternate landing strip.