diff --git a/src/airport_gui.cpp b/src/airport_gui.cpp
--- a/src/airport_gui.cpp
+++ b/src/airport_gui.cpp
@@ -154,7 +154,7 @@ static const WindowDesc _air_toolbar_des
 	WDP_ALIGN_TBR, 22, 64, 36, 64, 36,
 	WC_BUILD_TOOLBAR, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON | WDF_CONSTRUCTION,
-	NULL, _nested_air_toolbar_widgets, lengthof(_nested_air_toolbar_widgets)
+	_nested_air_toolbar_widgets, lengthof(_nested_air_toolbar_widgets)
 );
 
 void ShowBuildAirToolbar()
@@ -387,7 +387,7 @@ static const WindowDesc _build_airport_d
 	WDP_AUTO, WDP_AUTO, 148, 245, 148, 245,
 	WC_BUILD_STATION, WC_BUILD_TOOLBAR,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_CONSTRUCTION,
-	NULL, _nested_build_airport_widgets, lengthof(_nested_build_airport_widgets)
+	_nested_build_airport_widgets, lengthof(_nested_build_airport_widgets)
 );
 
 static void ShowBuildAirportPicker(Window *parent)