Apologies, no time to read through 42 pages to see if this has featured before:
Some US airports are the home of both military and civil operators.
Air traffic control is normally run by one side only.
One day the tower received a call from an aircraft asking, "What time is it?"
And responded, "Who is calling?"
The aircraft replied in a friendly voice, "What difference does it
make?"
And here the tower came into its own.
"It makes a lot of difference
If it is an American Airlines flight, it is 3 o'clock.
If it is an Air Force plane, 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.
If it is a Marine Corps aircraft, it's Thursday afternoon and 120
minutes to "Happy Hour."
And if it is a private executive jet we tell them that they can afford
to buy a watch.”