, ▁ 2 0 0 0 , ▁before ▁dis continu ing ▁non - stop ▁service ▁ 1 8 ▁months ▁later ▁and ▁dis continu ing ▁non - stop ▁Detroit - Be ij ing ▁service ▁in ▁ 2 0 0 2 . ▁( the ▁route ▁was ▁later ▁re - inst ated ▁on ▁July ▁ 1 , ▁ 2 0 1 1 ▁under ▁the ▁D elta ▁Air ▁L ines ▁brand ) ▁North west ▁Airlines ▁then ▁became ▁the ▁only ▁air line ▁author ized ▁to ▁fly ▁China ▁that ▁did ▁not ▁offer ▁any ▁non - stop ▁service ▁to ▁that ▁country ▁until ▁it ▁res umed ▁non - stop ▁fl ights ▁between ▁Detroit ▁and ▁Shang hai ▁on ▁June ▁ 1 , ▁ 2 0 0 9 ▁( as ▁part ▁of ▁its ▁new ▁parent , ▁D elta ▁Air ▁L ines ). ▁ ▁In ▁April ▁ 2 0 0 0 , ▁United ▁Airlines ▁dis cont in ued ▁Shang hai – T ok yo ▁service ▁and ▁launched ▁its ▁first ▁US – Ch ina ▁non - stop ▁service ▁from ▁San ▁Francisco ▁to ▁Shang hai . ▁In ▁June ▁ 2 0 0 0 , ▁United ▁Airlines ▁dis cont in ued ▁Be ij ing – T ok yo ▁service ▁and ▁started ▁non - stop ▁Be ij ing – San ▁Francisco ▁service . ▁This ▁replacement ▁of ▁services ▁was ▁done ▁because ▁of ▁the ▁restrictions ▁on ▁the ▁number ▁of ▁fl ights ▁permitted ▁under ▁the ▁ 1 9 9 9 ▁air ▁services ▁agreement . ▁Since ▁then , ▁all ▁China ▁routes ▁serv iced ▁by ▁United ▁Airlines ▁are ▁non - stop . ▁United