Snilloc Hmmmn.. I guess you're talking about "Sky-Babies"
Well the situation depends from one country to another. Depending on their laws
According to the United Nations, a baby born on a flight is a citizen of the country where the airline is registered. However, this is not always the case. Weirdly enough, despite its general adherence to jus soli, the United States will not recognize a baby birthed on a U.S. vessel unless it is docked at a U.S. port or flying within the country’s airspace.
So when pregnant and travelling to US always ensure you are travelling in a US aircraft 🛩