This is becoming less true, perhaps: modern road bikes now are largely made of carbon fibre, not aluminum. The cheap $1k ones are still Al, but anything over $

This is becoming less true, perhaps: modern road bikes now are largely made of carbon fibre, not aluminum. The cheap $1k ones are still Al, but anything over $2k is now CF. Of course, some commercial aircraft are now getting CF parts, but they're still mostly Al.