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Here's a puzzle I bet you've never pondered.

Imagine you are very, very pregnant. For the purposes of this mind game, you are a married American woman (with an American spouse) and you are about to board a plane and, pregnant as you are, they let you on.

Your flight, on Lufthansa Airlines, will leave Frankfurt, Germany, and travel nonstop to the Maldive Islands in the Indian Ocean. Germany is cold, wet and unhappy-making, and you crave the aquamarine waters, the balmy skies of the Maldives.

You take off. Then, hours later, just as your plane passes 37,000 feet above Karachi, Pakistan, heading south, your baby, in an inconvenient act of impetuosity, decides she wants to be born right then, right there — and so in row 13, business class seat 13B, you give birth to a healthy, somewhat surprised baby girl. The moment of birth happens as you are directly above Pakistani territory. Karachi is passing below as she emits her first cry. Everybody's fine — you, the baby, the crew.

Now comes my question. We've got an American mom on a German airplane in Pakistani airspace. What nationality is the baby?

Is she American? German? Pakistani? Maldivian? Or some combination of those? Baby's choice? Mom's? Pakistan's?

I ask because the question comes up in a book I'm reading, Unruly Spaces by Alastair Bonnett. It's a book that thinks a lot about place. In this case one of the pertinent questions is, "Who governs the air?"

Theirs All The Way Up To Heaven

There is an ancient doctrine, enshrined in English common law, that says Cuius est solum, eius est usque ad coelum et ad inferos, which means, "Whoever owns the soil, it is theirs all the way up to heaven and down to hell."

That was the old rule, before the advent of air balloons, then airplanes, then V2 rockets, then spy satellites. It's been seriously amended (at least in Britain) to a much more modest: You own the airspace necessary for "the use and enjoyment" of your plot of land. So how high up is that?

Apparently, not that high. Clouds, for example, don't belong to you.

Nations have made bolder claims to owning the sky. Some countries say their territory extends 43 miles up, some say 99. Everyone agrees there's an upper limit, but legal theories differ. One notion says when there's no longer enough air in the atmosphere to lift a plane, that's where outer (and shared) space begins. Others say the private zone must include the path of an orbiting satellite. Eight equatorial nations, in the Bogota Declaration of 1976, bumped their claims to 22,300 miles above earth — where geostationary spy satellites can park and look down.

The Airborne Baby Question

Whatever the reach of nations, most of the Earth is covered by ocean, and nobody owns the seas; so when traveling above the oceans, you are geopolitically nowhere or everywhere. There is, of course, a notion from admiralty law that says if your ship is French, then while onboard, you are legally in France.

Which means, writes Alastair Bonnett, "that if your plane is registered in Norway, even when you are in mid-Pacific, flying between Fiji and Tahiti, you are still in Norway and have to abide by Norwegian law." And that gets him to the Airborne Baby question:

This precept also suggests that babies born on planes will sometimes be citizens of the country where the plane is registered and sometimes take their parents' citizenship.

Apparently it depends. The national registry of the airline matters. The nation you are born over matters too. Some nations grant citizenship to fly-by babies. Some don't.

According to Alastair, "If you are born over the United States, in a foreign plane with foreign parents, you can still claim U.S. citizenship." Really? That's so generous! (Do Brazil, Russia, Egypt grant a flyover baby the same option?)

I may be the only person on Earth fascinated by this legal puzzle, but I bet there are some of you out there — lawyers, airline attendants, maybe even a real life "flyover baby" — who know if there's a general rule governing sky births. Is there a practice followed by most nations, or does every case turn on its details, on its particular who, when and where?

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