Despite the ubiquitous use of motion in animated displays, its impact may be minimal unless the motion can highlight task-relevant features. An examination of static vs. dynamic route presentations revealed that a continuous motion of routes in animated displays inhibited encoding of task- relevant landmarks - i.e. landmarks at turns - because the continuous motion focused participants' attention more equally across critical and less important landmarks along the route. These findings are relevant in research on air traffic controller displays. Current displays represent airplanes as "dots" that move at the radar update rate, typically every twelve seconds. With an upcoming GPS- based technology, some planes will be capable of providing aircraft position information at much faster update rates. The faster update rates have two potential implications for the display design. First, it is an open question whether a display with fast update rates, which resembles a dynamic motion display, will be better than a display with slower update rates that presents traffic information as a sequence of static images. Second, a mixture of aircraft with different update rates will be likely in the airspace until all aircrafts migrate to GPS-based technology, which may disrupt controllers' cognitive model of the airspace. This paper discusses these issues and some of the solutions considered by designers, users, and researchers in this field.