All these myths are related to giving birth on an airplane.
Myth 1) The child will obtain world citizenship.
Myth 2) The child obtains citizenship of the country the plane is flying over.
Myth 3) The child automatically becomes a citizen of the country in which the airline is registered.
Fact - In 99% of cases a newborn obtains the citizenship of his parents.
Myth 4) Most airlines give a child a free lifetime ticket if he or she is born on their plane.
Fact - No airline has confirmed that it is a hard and fast rule to give away free tickets for life, although this is an individual decision by the airline and not a consensus.
Another fact: Births on airplanes are very rare, especially since pregnant women cannot fly after a certain week (mostly 36). However, there are some cases of premature births on board.
Don't even think about giving birth on a plane with free tickets, because the crew isn't fully trained in childbirth. You'll have unnecessary complications during delivery and probably won't get free plane tickets. And forget about citizenship.