diff --git a/client/src/components/flightplanslayer/FlightPlansLayer.test.tsx b/client/src/components/flightplanslayer/FlightPlansLayer.test.tsx
new file mode 100644
index 00000000..8b2f6985
--- /dev/null
+++ b/client/src/components/flightplanslayer/FlightPlansLayer.test.tsx
@@ -0,0 +1,405 @@
+import { renderWithProviders } from "../../testutils";
+import FlightPlansLayer from "./FlightPlansLayer";
+import { PropsWithChildren } from "react";
+
+const mockPolyline = jest.fn();
+const mockLayerGroup = jest.fn();
+jest.mock("react-leaflet", () => ({
+  LayerGroup: (props: PropsWithChildren<any>) => {
+    mockLayerGroup(props);
+    return <>{props.children}</>;
+  },
+  Polyline: (props: any) => {
+    mockPolyline(props);
+  },
+}));
+
+// The waypoints in test data below should all use `should_make: false`. Markers
+// need useMap() to check the zoom level to decide if they should be drawn or
+// not, and we don't have good options here for mocking that behavior.
+describe("FlightPlansLayer", () => {
+  describe("unselected flights", () => {
+    it("are drawn", () => {
+      renderWithProviders(<FlightPlansLayer blue={true} />, {
+        preloadedState: {
+          flights: {
+            flights: {
+              foo: {
+                id: "foo",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+              bar: {
+                id: "bar",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+            },
+            selected: null,
+          },
+        },
+      });
+      expect(mockPolyline).toHaveBeenCalledTimes(2);
+      expect(mockLayerGroup).toBeCalledTimes(1);
+    });
+    it("are not drawn if wrong coalition", () => {
+      renderWithProviders(<FlightPlansLayer blue={true} />, {
+        preloadedState: {
+          flights: {
+            flights: {
+              foo: {
+                id: "foo",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+              bar: {
+                id: "bar",
+                blue: false,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+            },
+            selected: null,
+          },
+        },
+      });
+      expect(mockPolyline).toHaveBeenCalledTimes(1);
+      expect(mockLayerGroup).toBeCalledTimes(1);
+    });
+    it("are not drawn when only selected flights are to be drawn", () => {
+      renderWithProviders(<FlightPlansLayer blue={true} selectedOnly />, {
+        preloadedState: {
+          flights: {
+            flights: {
+              foo: {
+                id: "foo",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+            },
+            selected: null,
+          },
+        },
+      });
+      expect(mockPolyline).not.toHaveBeenCalled();
+      expect(mockLayerGroup).toBeCalledTimes(1);
+    });
+  });
+  describe("selected flights", () => {
+    it("are drawn", () => {
+      renderWithProviders(<FlightPlansLayer blue={true} />, {
+        preloadedState: {
+          flights: {
+            flights: {
+              foo: {
+                id: "foo",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+              bar: {
+                id: "bar",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+            },
+            selected: "foo",
+          },
+        },
+      });
+      expect(mockPolyline).toHaveBeenCalledTimes(2);
+      expect(mockLayerGroup).toBeCalledTimes(1);
+    });
+    it("are not drawn twice", () => {
+      renderWithProviders(<FlightPlansLayer blue={true} />, {
+        preloadedState: {
+          flights: {
+            flights: {
+              foo: {
+                id: "foo",
+                blue: true,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+            },
+            selected: "foo",
+          },
+        },
+      });
+      expect(mockPolyline).toHaveBeenCalledTimes(1);
+      expect(mockLayerGroup).toBeCalledTimes(1);
+    });
+    it("are not drawn if red", () => {
+      renderWithProviders(<FlightPlansLayer blue={false} selectedOnly />, {
+        preloadedState: {
+          flights: {
+            flights: {
+              foo: {
+                id: "foo",
+                blue: false,
+                sidc: "",
+                waypoints: [
+                  {
+                    name: "",
+                    position: {
+                      lat: 0,
+                      lng: 0,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                  {
+                    name: "",
+                    position: {
+                      lat: 1,
+                      lng: 1,
+                    },
+                    altitude_ft: 0,
+                    altitude_reference: "MSL",
+                    is_movable: true,
+                    should_mark: false,
+                    include_in_path: true,
+                    timing: "",
+                  },
+                ],
+              },
+            },
+            selected: "foo",
+          },
+        },
+      });
+      expect(mockPolyline).not.toHaveBeenCalled();
+      expect(mockLayerGroup).toBeCalledTimes(1);
+    });
+  });
+  it("are not drawn if there are no flights", () => {
+    renderWithProviders(<FlightPlansLayer blue={true} />);
+    expect(mockPolyline).not.toHaveBeenCalled();
+    expect(mockLayerGroup).toBeCalledTimes(1);
+  });
+});