diff --git a/game/theater/controlpoint.py b/game/theater/controlpoint.py
index ef4eed07..cec70fc0 100644
--- a/game/theater/controlpoint.py
+++ b/game/theater/controlpoint.py
@@ -8,7 +8,20 @@ from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
 from enum import Enum
 from functools import total_ordering
-from typing import Any, Dict, Iterator, List, Optional, Set, TYPE_CHECKING, Type, Union
+from typing import (
+    Any,
+    Dict,
+    Iterator,
+    List,
+    Optional,
+    Set,
+    TYPE_CHECKING,
+    Type,
+    Union,
+    Sequence,
+    Iterable,
+    Tuple,
+)
 
 from dcs.mapping import Point
 from dcs.ships import (
@@ -306,8 +319,8 @@ class ControlPoint(MissionTarget, ABC):
         # TODO: Should be Airbase specific.
         self.has_frontline = has_frontline
         self.connected_points: List[ControlPoint] = []
-        self.convoy_routes: Dict[ControlPoint, List[Point]] = {}
-        self.shipping_lanes: Dict[ControlPoint, List[Point]] = {}
+        self.convoy_routes: Dict[ControlPoint, Tuple[Point, ...]] = {}
+        self.shipping_lanes: Dict[ControlPoint, Tuple[Point, ...]] = {}
         self.base: Base = Base()
         self.cptype = cptype
         # TODO: Should be Airbase specific.
@@ -445,16 +458,18 @@ class ControlPoint(MissionTarget, ABC):
     def convoy_origin_for(self, destination: ControlPoint) -> Point:
         return self.convoy_route_to(destination)[0]
 
-    def convoy_route_to(self, destination: ControlPoint) -> List[Point]:
+    def convoy_route_to(self, destination: ControlPoint) -> Sequence[Point]:
         return self.convoy_routes[destination]
 
-    def create_convoy_route(self, to: ControlPoint, waypoints: List[Point]) -> None:
+    def create_convoy_route(self, to: ControlPoint, waypoints: Iterable[Point]) -> None:
         self.connected_points.append(to)
         self.stances[to.id] = CombatStance.DEFENSIVE
-        self.convoy_routes[to] = waypoints
+        self.convoy_routes[to] = tuple(waypoints)
 
-    def create_shipping_lane(self, to: ControlPoint, waypoints: List[Point]) -> None:
-        self.shipping_lanes[to] = waypoints
+    def create_shipping_lane(
+        self, to: ControlPoint, waypoints: Iterable[Point]
+    ) -> None:
+        self.shipping_lanes[to] = tuple(waypoints)
 
     @abstractmethod
     def runway_is_operational(self) -> bool:
diff --git a/game/theater/frontline.py b/game/theater/frontline.py
index 97ef6a9b..225980d1 100644
--- a/game/theater/frontline.py
+++ b/game/theater/frontline.py
@@ -52,7 +52,7 @@ class FrontLine(MissionTarget):
         self.blue_cp = blue_point
         self.red_cp = red_point
         try:
-            route = blue_point.convoy_route_to(red_point)
+            route = list(blue_point.convoy_route_to(red_point))
         except KeyError:
             # Some campaigns are air only and the mission generator currently relies on
             # *some* "front line" being drawn between these two. In this case there will
diff --git a/game/transfers.py b/game/transfers.py
index b531fce4..4bdff773 100644
--- a/game/transfers.py
+++ b/game/transfers.py
@@ -4,7 +4,17 @@ import logging
 from collections import defaultdict
 from dataclasses import dataclass, field
 from functools import singledispatchmethod
-from typing import Dict, Generic, Iterator, List, Optional, TYPE_CHECKING, Type, TypeVar
+from typing import (
+    Dict,
+    Generic,
+    Iterator,
+    List,
+    Optional,
+    TYPE_CHECKING,
+    Type,
+    TypeVar,
+    Sequence,
+)
 
 from dcs.mapping import Point
 from dcs.unittype import FlyingType, VehicleType
@@ -363,7 +373,7 @@ class CargoShip(MultiGroupTransport):
         yield from super().mission_types(for_player)
 
     @property
-    def route(self) -> List[Point]:
+    def route(self) -> Sequence[Point]:
         return self.origin.shipping_lanes[self.destination]
 
     def description(self) -> str: