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 do planes fly? If you've ever watched a jet plane taking off or coming in to land, the first thing you'll have noticed is the noise of the engines. Jet engines, which are long metal tubes burning a continuous rush of fuel and air, are far noisier (and far more powerful) than traditional propeller engines.