Air pocket

Air Pocket. An erroneous term describing the effect of vertical currents which cause 'bumps' to a flying machine passing through them.
Airport. An aerodrome provided with Customs amenities and used as a station on a commercial airway.

Clear (or glaze) ice is sometimes clear and smooth, but usually contains some air pockets that result in a lumpy translucent appearance.

Transparent compared to rime ice. Has a clear and smooth surface (think ice cubes), can have air pockets and initially follows the surface but with higher accretion it becomes lumpy.
Effects of ice ...