Schedule vs. itinerary vs. agenda vs. timetable

Schedule/行程(表) vs. itinerary/旅行計劃 vs. agenda/議程vs. timetable/時刻表：

1. schedule/行程/時程(表)，表示一連串活動/事件發生的時間(可能包含地點)，多用在工作或事件時間的排程或進度上；(美)可用在交通工具時間表或學校課程表上。

Could you help fit me into his tight schedule?
I expect this project to be finished on schedule.
What's Tim's class schedule this semester?
Here is the schedule of city bus(US).

2. itinerary(n.a.)/旅行計劃(的)，多用在旅程相關的活動計劃/時間安排上，包含遊玩與出差的行程：

The travel agent will have my itinerary ready tomorrow morning.
Your flight no. will be shown on your itinerary.

3. agenda/議程(表)/日常工作項目，多出現在會議裡面，指的是一連串需要被討論的事情(可能有或沒有表定的時間)。"agenda"與"schedule"用法的差異，通常在你的行程(schedule)裡會有很多會議(meeting)，但一個會議只有一個議程(agenda)；agenda另外也用在日常生活工作項目：

The agenda of this meeting will be emailed to you a week before the meeting time.
The boss would like us to list our agendas of today first.

4. Timetable/時間表/時刻表/課程表，一連串事件或計劃發生的時間表，(英)常用在交通工具時程與學校課程表上：

I wish I did not have a busy timetable next month.
Excuses me, where can I get the timetable for the train to London?
I have "Introduction to British Literature"on my timetable every Monday morning this semester.


On my mind:
I never think it will be this complicated. Originally, I am just curious about the different usage between "schedule" and "itinerary". It turns out that "agenda" and "timetable"appears in the usage discussion as well. Since I am going to deal with them, it is better to deal with them all at once.