We often think of freedom as a choice. This is true on the human level but freedom has deep roots in the nature of things. "All things derive from love, aspire to love, and move impelled by love, though naturally with varying degrees of awareness and freedom." (Pope Benedict XVI)
What is love? In the most universal sense love is the movement of creatures toward their proper good which is ultimately God and this movement necessitates a certain degree of freedom. For example, atoms are free to act according to their nature, that is with purpose towared an end. Our hearts keep beating without us willing it, that is necessarily and unless this were so, we would have no freedom of choice. A plant has a freedom to grow but not move. Clouds are formed by thermo-dynamic energy and move by the force of wind. A bird can move in a sea of air but not in one of water; a goat has instinctive freedom to seek food, move by its inner dynamics and reproduce but it does not have the freedom to think rationally. etc.
Freedom of creatures is also dependent on environmental factors. The fish is free to swim in the water, to seek food in the water and to reproduce in the water. God designed fish-nature to live in water. It is also free to leave the water, as some whales have done, with the consequence of death. Likewise, man is meant to live in a sea of air which provides the pressure and oxygen for life. A shot time without air to breathe and we die. Yes, we can live in space as long as we carry with us the air and food for living. Our physical freedom is therefore limited by our nature compose of body and soul. Yes, we are free to jump out a window, that is to disobey the law of gravity with the direct consequences of suffering and death. Absolute freedom belongs only to God while freedom of creatures is a contingent or a dependent freedom with their ultimate dependence of God.