Because these are installations leased to Americans they donu2019t own their bases abroad itu2019s not actual US soil but note this doesnu2019t include Embassies Ships or Planes anyone born on these things registered to the US government are citizens. If you dropped a kid right on the steps or in the foyer of an American Embassy then that kid is a US Citizen. People born on planes flying over America or if the plane is registered in America they too are citizens possibly other citizenship too if flying over a country that allows birthright citizenship.