일정 = schedule or itinerary (with detailed timetable). Can be used for both planned and already past one. 예정 = planned schedule (usually of a single trip or activity). 계획 = plan (often just an intention without elaborate timetable). All three can have the -표 suffix. 표 in this case means a table or chart showing the schedule(일정표, 예정표) or plan(계획표), either on a sheet of paper or a computer or other screen. e.g. - 이번 여행 일정은 너무 급박하다 = The schedule for this trip is too tight. - 그는 어려운 일정을 소화했다 = He managed a difficult schedule. - 저는 다음 주에 부산으로 떠날 예정이에요 = I am scheduled to leave for Busan next week. - 예정에 없던 일이 생겼다 = Something unanticipated has come up. - 나는 내년에 대학에 진학할 계획이에요 = I'm planning to study in college next year. - 모든 일이 계획한 대로 되지는 않는다 = Not everything will go according to your plan.

일정표, 예정표, 계획표 is for physical object. 표 is time table Just 'schedule' case, 일정, 예정, 계획(표) can be used