Why is 1159 am immediately followed by 1200 pm & 1159 pm followed by 1200am ? Should not 1200 noon be 12 am ( & 1201 be pm as it is ) & 1200 midnight be 1200am ? To add European & UK timetables use the 24 hour clock which seems to me to make more sense than US timetables where pm's are listed in heavy print & on a 12 hour clock cycle .

Because the 12 hour clock is a simplification of the 24 hour clock where 12am is clearly 0000.

 

And yes for formal time giving I'd say 24h was better, but when talking to people I nearly always use 12 hour. And my watches have always been 12 hour...

Strictly speaking, 12 noon is 12 noon, period. Designating 12 noon as AM or PM is a contradiction in terms. AM means before noon, PM means after noon.

 

We say 12 noon is 12:00 PM because even a tiny fraction of a second after noon is after noon: Such a time gets the PM designator when using a 12-hour clock. It makes more sense for the AM/PM designator to switch in sync with the hour than some infinitesimal time after the hour, does it not?

I understand all international navigational travel uses Zulu ( UTC , GMT ) time but does air travel in continental US do the same ?