Wings are freedom only when they are wide open in flight. On one’s back they are a heavy weight.

[Крылья — свобода, только когда раскрыты в полёте, за спиной они — тяжесть.]

Marina Tsvetaeva (1892-1941) Russian poet

Notebook 1 (1921)
    (Source)

Literally "Wings -- freedom, only when opened in flight, behind their backs -- heavy."