Possible Clues:

• Would sound so light that it turns a bit flat
• Would be alight, by the sound of it?
• Get a lump of wood back if it's 28 across
• Material for a small airplane
• Tree with light soft wood
• It's lighter, but not for firewood
• Light construction material
• Plane material
• Kon-Tiki's makeup
• Lake accommodating sailor's first light raft