diff --git a/scripts/dev-server.mjs b/scripts/dev-server.mjs
index 62b6c7dc..72198aa4 100644
--- a/scripts/dev-server.mjs
+++ b/scripts/dev-server.mjs
@@ -133,10 +133,14 @@ function execCurl(args, res) {
       return;
     }
 
-    // stdout = body + "\n" + statusCode (from -w "\n%{http_code}")
+    // stdout = body + "\n" + statusCode (from -w "\n%{http_code}"). When
+    // upstream returns an empty body the stdout starts with "\n", so a
+    // `> 0` check mis-treats the status as body and falls back to 200 —
+    // silently hiding real 4xx/5xx responses. Use `>= 0` and split
+    // unconditionally when the newline is present.
     const lastNewline = stdout.lastIndexOf("\n");
-    const body = lastNewline > 0 ? stdout.substring(0, lastNewline) : stdout;
-    const statusStr = lastNewline > 0 ? stdout.substring(lastNewline + 1).trim() : "200";
+    const body = lastNewline >= 0 ? stdout.substring(0, lastNewline) : stdout;
+    const statusStr = lastNewline >= 0 ? stdout.substring(lastNewline + 1).trim() : "200";
     const status = parseInt(statusStr) || 200;
 
     const isJson = body.trimStart().startsWith("{") || body.trimStart().startsWith("[");
diff --git a/src/features/flights-map/api.test.ts b/src/features/flights-map/api.test.ts
index 93338e01..1c4ac571 100644
--- a/src/features/flights-map/api.test.ts
+++ b/src/features/flights-map/api.test.ts
@@ -68,8 +68,8 @@ describe("searchDestinations", () => {
     expect(url.pathname).toBe("/flights/1/ru/destinations");
     expect(url.searchParams.get("departure")).toBe("SVO");
     expect(url.searchParams.get("arrival")).toBe("LED");
-    expect(url.searchParams.get("dateFrom")).toBe("20250601");
-    expect(url.searchParams.get("dateTo")).toBe("20251201");
+    expect(url.searchParams.get("dateFrom")).toBe("2025-06-01");
+    expect(url.searchParams.get("dateTo")).toBe("2025-12-01");
     expect(url.searchParams.get("connections")).toBe("0");
   });
 
@@ -143,7 +143,7 @@ describe("getFlightsMapCalendar", () => {
     });
 
     const url = extractUrl(mockFetch);
-    expect(url.pathname).toBe("/flights/v1/ru/days/20250601/200/route/SVO-LED/flights-map/");
+    expect(url.pathname).toBe("/flights/v1/ru/days/2025-06-01/200/route/SVO-LED/flights-map/");
   });
 
   it("builds correct path for connecting route", async () => {
@@ -158,7 +158,7 @@ describe("getFlightsMapCalendar", () => {
 
     const url = extractUrl(mockFetch);
     expect(url.pathname).toBe(
-      "/flights/v1/ru/days/20250601/200/connections/SVO-LED-1/flights-map/",
+      "/flights/v1/ru/days/2025-06-01/200/connections/SVO-LED-1/flights-map/",
     );
   });
 
@@ -172,7 +172,7 @@ describe("getFlightsMapCalendar", () => {
     });
 
     const url = extractUrl(mockFetch);
-    expect(url.pathname).toBe("/flights/v1/ru/days/20250601/200/departure/SVO/flights-map/");
+    expect(url.pathname).toBe("/flights/v1/ru/days/2025-06-01/200/departure/SVO/flights-map/");
   });
 
   it("parses binary days string into available date strings", async () => {
diff --git a/src/features/flights-map/api.ts b/src/features/flights-map/api.ts
index f32b747f..7a47c9cc 100644
--- a/src/features/flights-map/api.ts
+++ b/src/features/flights-map/api.ts
@@ -27,10 +27,13 @@ export async function searchDestinations(
   client: ApiClient,
   params: FlightsMapSearchParams,
 ): Promise<IDestinationsResponse> {
+  // Upstream expects yyyy-MM-DD with dashes on /destinations; internal callers
+  // pass the compact yyyyMMdd we use everywhere else in the app. Matches
+  // Angular's ApiFormatterService.formatDateOnly output.
   const query: Record<string, string> = {
     departure: params.departure,
-    dateFrom: params.dateFrom,
-    dateTo: params.dateTo,
+    dateFrom: toDashedDate(params.dateFrom),
+    dateTo: toDashedDate(params.dateTo),
     connections: String(params.connections ?? 0),
   };
 
@@ -41,6 +44,14 @@ export async function searchDestinations(
   return client.get<IDestinationsResponse>(`flights/1/${client.locale}/destinations`, query);
 }
 
+function toDashedDate(yyyymmdd: string): string {
+  if (/^\d{8}$/.test(yyyymmdd)) {
+    return `${yyyymmdd.slice(0, 4)}-${yyyymmdd.slice(4, 6)}-${yyyymmdd.slice(6, 8)}`;
+  }
+  // Already dashed (or something else) — pass through.
+  return yyyymmdd;
+}
+
 /**
  * Get available calendar days for a flights-map route.
  * Maps to: `GET days/{date}/200/{routeSegment}/flights-map/v1`
@@ -56,7 +67,8 @@ export async function getFlightsMapCalendar(
   const routeSegment = buildRouteSegment(params);
   if (!routeSegment) return [];
 
-  const path = `flights/v1/${client.locale}/days/${params.date}/200/${routeSegment}/flights-map/`;
+  // Upstream expects yyyy-MM-DD with dashes on the /days path too.
+  const path = `flights/v1/${client.locale}/days/${toDashedDate(params.date)}/200/${routeSegment}/flights-map/`;
   const response = await client.get<IFlightsMapDaysResponse>(path);
   return parseBinaryDays(response.days, params.date);
 }