diff --git a/src/aircraft_cmd.cpp b/src/aircraft_cmd.cpp
--- a/src/aircraft_cmd.cpp
+++ b/src/aircraft_cmd.cpp
@@ -1786,7 +1786,7 @@ static bool AirportMove(Aircraft *v, con
 {
 	/* error handling */
 	if (v->pos >= apc->nofelements) {
-		DEBUG(misc, 0, "[Ap] position %d is not valid for current airport. Max position is %d", v->pos, apc->nofelements-1);
+		Debug(misc, 0, "[Ap] position {} is not valid for current airport. Max position is {}", v->pos, apc->nofelements-1);
 		assert(v->pos < apc->nofelements);
 	}
 
@@ -1825,7 +1825,7 @@ static bool AirportMove(Aircraft *v, con
 		current = current->next;
 	} while (current != nullptr);
 
-	DEBUG(misc, 0, "[Ap] cannot move further on Airport! (pos %d state %d) for vehicle %d", v->pos, v->state, v->index);
+	Debug(misc, 0, "[Ap] cannot move further on Airport! (pos {} state {}) for vehicle {}", v->pos, v->state, v->index);
 	NOT_REACHED();
 }