What atmospheric pressure measurement unit is commonly used in aviation?

In aviation, atmospheric pressure is most commonly measured in inches of mercury. This unit is derived from the barometer, which uses a column of mercury to determine pressure based on the height of the mercury column. It is a traditional measure that has been widely adopted in the United States and is particularly relevant in aviation for altimeter settings, which pilots use to maintain their altitude safely and accurately during flight.

Other options, such as pascals and kilopascals, are more widely used in scientific contexts and may not be as familiar to pilots and those in the aviation industry. The bar is also a measurement of pressure, but it is not as common in aviation practice, particularly in the United States. Thus, inches of mercury remain the standard unit utilized for atmospheric pressure in aviation settings, aligning closely with the altimeter reference used during flights.