diff --git a/src/features/flights-map/filterRoutes.test.ts b/src/features/flights-map/filterRoutes.test.ts
new file mode 100644
index 00000000..6a104d48
--- /dev/null
+++ b/src/features/flights-map/filterRoutes.test.ts
@@ -0,0 +1,142 @@
+import { describe, it, expect } from "vitest";
+import { filterRoutes } from "./filterRoutes.js";
+import { transformDictionaries } from "@/shared/dictionaries/index.js";
+import type { IFlightRoute, IFlightsMapFilterState } from "./types.js";
+import type { IDictionaries, IRawDictionaries } from "@/shared/dictionaries/index.js";
+
+const raw: IRawDictionaries = {
+  regions: [],
+  countries: [
+    { code: "RU", title: { ru: "Россия" }, world_region_id: 500374 },
+    { code: "US", title: { ru: "США" }, world_region_id: 1 },
+  ],
+  cities: [
+    { code: "MOW", title: { ru: "Москва" }, country_code: "RU", has_afl_flights: true, location: { lat: 55, lon: 37 } },
+    { code: "LED", title: { ru: "Санкт-Петербург" }, country_code: "RU", has_afl_flights: true, location: { lat: 60, lon: 30 } },
+    { code: "AER", title: { ru: "Сочи" }, country_code: "RU", has_afl_flights: true, location: { lat: 43, lon: 39 } },
+    { code: "NYC", title: { ru: "Нью-Йорк" }, country_code: "US", has_afl_flights: true, location: { lat: 40, lon: -74 } },
+  ],
+  airports: [
+    { code: "SVO", city_code: "MOW", title: { ru: "Шереметьево" }, has_afl_flights: true, location: { lat: 55, lon: 37 } },
+    { code: "JFK", city_code: "NYC", title: { ru: "Джон Кеннеди" }, has_afl_flights: true, location: { lat: 40, lon: -74 } },
+    { code: "LED", city_code: "LED", title: { ru: "Пулково" }, has_afl_flights: true, location: { lat: 60, lon: 30 } },
+    { code: "AER", city_code: "AER", title: { ru: "Сочи" }, has_afl_flights: true, location: { lat: 43, lon: 39 } },
+  ],
+};
+
+const d: IDictionaries = transformDictionaries(raw, "ru");
+
+function filter(
+  overrides: Partial<IFlightsMapFilterState> = {},
+): IFlightsMapFilterState {
+  return {
+    connections: false,
+    domestic: false,
+    international: false,
+    ...overrides,
+  };
+}
+
+describe("filterRoutes — empty and passthrough", () => {
+  it("returns [] for no routes", () => {
+    expect(filterRoutes([], filter(), d)).toEqual([]);
+  });
+
+  it("returns routes unchanged when no toggles are active", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["MOW", "LED"], isDirect: true },
+      { route: ["MOW", "NYC"], isDirect: true },
+    ];
+    expect(filterRoutes(routes, filter(), d)).toEqual(routes);
+  });
+});
+
+describe("filterRoutes — domestic", () => {
+  it("keeps only routes where every city is RU", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["MOW", "LED"], isDirect: true },
+      { route: ["MOW", "NYC"], isDirect: true },
+    ];
+    const out = filterRoutes(routes, filter({ domestic: true }), d);
+    expect(out).toHaveLength(1);
+    expect(out[0]!.route).toEqual(["MOW", "LED"]);
+  });
+});
+
+describe("filterRoutes — international", () => {
+  it("keeps only routes with at least one non-RU city", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["MOW", "LED"], isDirect: true },
+      { route: ["MOW", "NYC"], isDirect: true },
+    ];
+    const out = filterRoutes(routes, filter({ international: true }), d);
+    expect(out).toHaveLength(1);
+    expect(out[0]!.route).toEqual(["MOW", "NYC"]);
+  });
+});
+
+describe("filterRoutes — both domestic AND international", () => {
+  it("applies no domestic/intl filter when both are true", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["MOW", "LED"], isDirect: true },
+      { route: ["MOW", "NYC"], isDirect: true },
+    ];
+    const out = filterRoutes(
+      routes,
+      filter({ domestic: true, international: true }),
+      d,
+    );
+    expect(out).toEqual(routes);
+  });
+});
+
+describe("filterRoutes — connections", () => {
+  it("keeps only non-direct routes", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["MOW", "LED"], isDirect: true },
+      { route: ["MOW", "X", "LED"], isDirect: false },
+    ];
+    const out = filterRoutes(routes, filter({ connections: true }), d);
+    expect(out).toHaveLength(1);
+    expect(out[0]!.route).toEqual(["MOW", "X", "LED"]);
+  });
+});
+
+describe("filterRoutes — airport-code normalization", () => {
+  it("treats airport codes (SVO, JFK) as their city codes (MOW, NYC)", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["SVO", "JFK"], isDirect: true },
+      { route: ["SVO", "LED"], isDirect: true },
+    ];
+    const intl = filterRoutes(routes, filter({ international: true }), d);
+    expect(intl).toHaveLength(1);
+    expect(intl[0]!.route).toEqual(["SVO", "JFK"]);
+
+    const dom = filterRoutes(routes, filter({ domestic: true }), d);
+    expect(dom).toHaveLength(1);
+    expect(dom[0]!.route).toEqual(["SVO", "LED"]);
+  });
+
+  it("drops routes containing unknown codes when any toggle is active", () => {
+    const routes: IFlightRoute[] = [{ route: ["MOW", "???"], isDirect: true }];
+    expect(filterRoutes(routes, filter({ domestic: true }), d)).toEqual([]);
+    expect(filterRoutes(routes, filter({ international: true }), d)).toEqual([]);
+  });
+});
+
+describe("filterRoutes — combo", () => {
+  it("applies domestic + connections together", () => {
+    const routes: IFlightRoute[] = [
+      { route: ["MOW", "LED"], isDirect: true },
+      { route: ["MOW", "AER", "LED"], isDirect: false },
+      { route: ["MOW", "NYC"], isDirect: false },
+    ];
+    const out = filterRoutes(
+      routes,
+      filter({ domestic: true, connections: true }),
+      d,
+    );
+    expect(out).toHaveLength(1);
+    expect(out[0]!.route).toEqual(["MOW", "AER", "LED"]);
+  });
+});
diff --git a/src/features/flights-map/filterRoutes.ts b/src/features/flights-map/filterRoutes.ts
new file mode 100644
index 00000000..f9363972
--- /dev/null
+++ b/src/features/flights-map/filterRoutes.ts
@@ -0,0 +1,45 @@
+/**
+ * Client-side route filter matching Angular `filterRoutes`.
+ *
+ * Rules:
+ *   - domestic && !international → keep routes where every city is RU.
+ *   - international && !domestic → keep routes with at least one non-RU city.
+ *   - both domestic && international → no domestic/intl filter (show all).
+ *   - connections → keep only routes where isDirect is false.
+ *
+ * City codes and airport codes both appear in route arrays; we normalize each
+ * entry to its city code before set-membership checks.
+ */
+
+import type { IDictionaries } from "@/shared/dictionaries/index.js";
+import { getCityCodeByAirportCode } from "@/shared/dictionaries/index.js";
+import type { IFlightRoute, IFlightsMapFilterState } from "./types.js";
+
+export function filterRoutes(
+  routes: IFlightRoute[],
+  filter: Pick<IFlightsMapFilterState, "domestic" | "international" | "connections">,
+  dictionaries: IDictionaries,
+): IFlightRoute[] {
+  const { domestic, international, connections } = filter;
+
+  const toCityCode = (code: string): string =>
+    getCityCodeByAirportCode(dictionaries, code) ?? code;
+
+  const isDomestic = (r: IFlightRoute): boolean =>
+    r.route.every((code) => dictionaries.ruCityCodes.has(toCityCode(code)));
+
+  const isInternational = (r: IFlightRoute): boolean =>
+    r.route.some((code) => dictionaries.otherCityCodes.has(toCityCode(code)));
+
+  const hasConnections = (r: IFlightRoute): boolean => !r.isDirect;
+
+  const predicates: Array<(r: IFlightRoute) => boolean> = [];
+
+  if (domestic && !international) predicates.push(isDomestic);
+  else if (international && !domestic) predicates.push(isInternational);
+
+  if (connections) predicates.push(hasConnections);
+
+  if (predicates.length === 0) return routes;
+  return routes.filter((r) => predicates.every((p) => p(r)));
+}