The crossword solution for the term HEAD FOR THE RUNWAY is TAXI, which is a four-letter word. Taxiing is the process of maneuvering an aircraft on the ground, either to take off or land. It involves the aircraft moving along the runway under its own power, rather than being towed by another vehicle. The term 'head for the runway' is used to describe the process of taxiing an aircraft to the runway in preparation for takeoff.