Cool :)
I would assume that this is one of these: http://www.michaltrpak.com/en/stranka/sochy/slight-uncertainty/1561/
As explained by the artist himself in the article above: "Slight Uncertainty is a project hung behind the office windows. Slight because of seeming lightness of flying but uncertain because of unsure landing and unknown length of the flight. This might be kind of a paraphrase of the economic crisis. "

(I have allowed myself to correct two typos in the quoted text)