Riddle Me This

A cousin to night, but not to day,
A wind trapped leaf that has gone astray,
The first of the first, the last of the last,
The fate of a soldier whose flag flies half-mast,
What man has achieved, but will never master,
The goal of the tailed diamond, speeding faster and faster,
The dream of the new bird, and memoirs of the ace,
The one possible exit that leads into space,
The golden bird rises from its fiery lair,
With its head in the clouds and its song in the air,
The path of the fair one, too beautiful to be,
Whose true joy only the dead will see.