Weaning Your Baby Onto Solids. The term 'to wean' comes from an ancient phrase that means 'to accustom to'. So weaning refers to the period during which an infant gradually becomes accustomed to food other than milk (breast or formula). Up until 6 months of age, breast or formula milk alone is nutritionally adequate.
Occasional airplane vibration during flight is not unusual. There are many causes of airplane vibration, including landing gear extension and retraction, extension of speed brakes, free play in movable surfaces, and systems malfunctions.
How Airplanes and Aircraft Fly The Bernoulli Principle Airplanes fly when the movement of air across their wings creates an upward force on the wings (and thus the rest of the plane) that is greater than the force of gravity pulling the plane toward the earth.