Fauconnier and Turner’s conceptual blending theory (1998) has been used to analyze many types of cognitive phenomena, particularly the role blending plays in language comprehension. In this paper we illustrate how blending also has a role in mediating expert performance, such as understanding the meaning of a chart or a navigation display. Pilots use blends to assess flight situations, predict what the airplane will do next, and make decisions. These blended conceptualizations of navigational tools help the pilot to interact appropriately with the aircraft. We propose that the principles of conceptual blending theory aid in the 1design and testing of novel display designs.