Millionsofaircrafttakeoffaroundtheworldeveryyear.Theski...
问题详情:Millionsofaircrafttakeoffaroundtheworldeveryyear.Theskiestheyflyinseemlimitless-milesofemptyspace.But,withthenumberofflightsincreasingeachyear,thisemptinessnolongerexists.Researchersintheworld...