diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index da2e43dfe8..bee83a84c9 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -1414,7 +1414,7 @@ uint GetVehicleCapacity(const Vehicle *v, uint16 *mail_capacity)
 	 * Note: This might change to become more consistent/flexible. */
 	if (e->type != VEH_SHIP) {
 		if (e->type == VEH_AIRCRAFT) {
-			if (!IsCargoInClass(v->cargo_type, CT_PASSENGERS)) {
+			if (!IsCargoInClass(v->cargo_type, CC_PASSENGERS)) {
 				capacity += e->u.air.mail_capacity;
 			}
 			if (v->cargo_type == CT_MAIL) return capacity;