On some air bases the Air Force is on one
side of the field and civilian aircraft use the other side of the field, with the control
tower in the middle. One day the tower received a call from an aircraft asking, "What
time is it?"
The tower responded, "Who is
calling?"
The aircraft replied, "What difference
does it make?"
The tower replied, "It makes a lot of
difference. If it is an American Airlines Flight, it is 3 o'clock. If it is an Air Force,
it is 1500 hours. If it is a Navy aircraft, it is 6 bells. If it is an Army aircraft, the
big hand is on the 12 and the little hand is on the 3."