How might strategic, operational, and tactical planning complement one another in an organization?
These three types of planning can complement one another if they are undertaken in a coordinated way.
Of course, it is always necessary to make sure that the "higher" types of planning inform the "lower" ones. If a firm has a strategic plan, it must ensure that the outlines of this plan determine the nature of the tactical plans. If this does not happen, the firm's strategic plans will never be carried out in reality.
However, it is also a good idea to allow lessons from the lower-level plans to inform higher level planning. If operational planning reveals that there are problems with the tactical plan, the tactical plan must be reevaluated. The "ground level" realities must be used to help to adjust higher level plans for the future.
If these things are done, the various levels of planning will complement one another and be of benefit to the firm.