how many of us can not truly say , that at some time , we have looked up and chanced to glimpse a passenger jet breaking through a cloud , or flying all alone in a perfect , clear blue sky , and not felt a sense of awe : not awe at mans ingenuity and invention , but in the pure , physical spectacle of several hundred tonnes of moulded aluminium alloy up so high , where we unaided can not presume to go .