É archaeologists have been racking their brains over the geometric system of lines, animal drawings and neatly arranged bits of stone which extend over an area some 30 miles long between Palpa in the north and Nazca in the south.  To me, they look just like an airport layoutÉ (Gods from Outer Space, 115)
At some time in the past, unknown intelligences landed on the uninhabited plain near the present-day town of Nazca and built an improvised airfield for their spacecraft which were to operate in the vicinity of the earth. (Gods from Outer Space, 117)