Time Check

It's radio conversation:

...........

PILOT: Oshkosh tower could you please give me a time check?

TOWER: Please identify yourself.

PILOT: What difference does it make. I only want a time check!

TOWER: It makes a BIG difference. If you are general aviation, it's 4:30. If you are military it's 16:30. If you are Lufthansa it's 22:30 Zulu,.... and if you're an ultralight, it's Thursday!