Men of the Sky (1931)

In the years before World War I, a love affair takes place between an American pilot named Jack Ames and a French spy named Madeleine Aubert. Madeleine leaves her American fiancé to join her father, another French spy, at an estate in Germany. Her father instructs her to accept the invitation of a Prussian officer, Eric von Coburg, to live at his estate for a month.