Calama is the nearest airport to San Pedro de Atacama, a small pueblo in the middle of the Atacama Desert.
The first flight took an hour and twenty minutes to go from Santiago to Copiapo. After a brief layover, we then flew another hour further north to Calama.
My flights delivered me from Santiago to Calama in two and a half hours, whereas the bus, though cheaper, takes 24 hours.
And from what I've heard, it's tedious and boring (you're driving through the desert after all), so do yourself a favor and spend the extra money to fly.