The times for calendar entries change as you move between time zones. This is potentially disastrous. You live in the west but fly to the east coast. When you made your plane reservations, you entered the flight time in the local time, but when you've flown east and are looking up when your return flight leaves, the calendar will show the wrong time -- it will show the flight time as three hours later than it really is.
The calendar should not be linked to the clock.