--- a/aircraft_cmd.c	Wed Dec 14 06:16:34 2005 +0000
+++ b/aircraft_cmd.c	Wed Dec 14 06:20:23 2005 +0000
@@ -121,7 +121,7 @@
 	}
 }
 
-int32 EstimateAircraftCost(EngineID engine_type)
+static int32 EstimateAircraftCost(EngineID engine_type)
 {
 	return AircraftVehInfo(engine_type)->base_cost * (_price.aircraft_base>>3)>>5;
 }