Just read an article about when flying with babies and very small children via commercial airlines.

It said that babies/ small children should only be allowed to fly when in their “own” seat and in a carrier (infant/child carrier seat) as required when in a car.

Yes, that means you must purchase a seat ticket for everyone. If required for children when being transported in a car, they should also be required in an aircraft. Make a decision then read the side note.

Side note: Several years ago in Oklahoma City’s FAA test facility representing the Canadian Aviation Safety Board tests of infants restraint systems for babies on adults’ laps were being tested.

They used mannequins which had the size and weight repartition similar to that of an average infant. They also had a bladder inside the mannequin to measure the internal pressure. The idea at the time was to evaluate the “loop and strap” system that some airlines were already promoting and using as a safety device for infants on parents’ laps. It consisted of a loop around the adult’s seatbelt strap and a belt around the baby with a short strap attaching the loop to the baby’s strap.

After the tests, the anthropomorphologist who designed the mannequins was stunned: he had never seen a bladder made of thick rubber explode inside one of his mannequins! The baby was doomed two ways: the pressure that would destroy the internal organs, and the hull fracture against the bottom of the seat in front of the baby in the adult’s lap.

Furthermore, this adult would also be killed because of his/her body’s belly violently wrapping around the baby’s body. For the adult, the internal pressure wouldn’t be survivable. I believe the tests were done in the late 80’s, early 90’s.