diff --git a/airtrail_client.py b/airtrail_client.py
index 962f989..afc19b8 100644
--- a/airtrail_client.py
+++ b/airtrail_client.py
@@ -91,17 +91,43 @@ def downsample_track(
     return new_coords, new_times
 
 
+def _hhmm(iso_str: str | None) -> str | None:
+    """Extract 'HH:MM' from one of our seconds-precision ISO datetime
+    strings (e.g. '2026-09-13T13:57:00+10:00' -> '13:57').
+
+    AirTrail does NOT read the time-of-day out of departure/arrival/
+    departureScheduled/etc. at all - confirmed against its source
+    (src/lib/server/utils/flight.ts + src/lib/utils/datetime/parse.ts's
+    mergeTimeWithDate()): it takes only the DATE portion of that field and
+    merges it with a separate companion '*Time' field (departureTime,
+    arrivalTime, departureScheduledTime, ...) for the actual clock time,
+    interpreted in the airport's own timezone. Sending a fully-populated
+    ISO datetime without its companion Time field means AirTrail silently
+    drops the time for departure/departureScheduled/etc., and outright
+    rejects arrival with "Cannot have arrival date without time" - both
+    confirmed live. Every date field this module sets below needs its
+    matching *Time companion or the value doesn't actually land."""
+    if not iso_str:
+        return None
+    return iso_str[11:16]
+
+
 def build_save_payload(row: dict, existing_id: int | None) -> dict:
     flight_number = f"{row.get('operating_carrier_iata') or ''}{row.get('flight_number') or ''}"
     flight_date_str = row["flight_date"]
 
+    departure_value = row.get("gate_departure_actual") or f"{flight_date_str}T00:00:00.000+00:00"
+
     payload = {
         "from": row["from_iata"],
         "to": row["to_iata"],
         # Falls back to the bare date (day precision, no time) exactly like
         # before if AeroDataBox never returned a gate-actual time - e.g. no
-        # AERODATABOX_API_KEY configured, or the lookup came up empty.
-        "departure": row.get("gate_departure_actual") or f"{flight_date_str}T00:00:00.000+00:00",
+        # AERODATABOX_API_KEY configured, or the lookup came up empty. No
+        # departureTime is set in that case, which AirTrail treats the same
+        # way (silently date-only) rather than erroring - unlike arrival.
+        "departure": departure_value,
+        "departureTime": _hhmm(row.get("gate_departure_actual")),
         "datePrecision": "day",
         "flightNumber": flight_number or None,
         "airline": row.get("operating_carrier_icao"),
@@ -128,14 +154,22 @@ def build_save_payload(row: dict, existing_id: int | None) -> dict:
     # manual Search remains the fallback, same as before this change.
     if row.get("gate_departure_scheduled"):
         payload["departureScheduled"] = row["gate_departure_scheduled"]
+        payload["departureScheduledTime"] = _hhmm(row["gate_departure_scheduled"])
     if row.get("gate_arrival_scheduled"):
         payload["arrivalScheduled"] = row["gate_arrival_scheduled"]
+        payload["arrivalScheduledTime"] = _hhmm(row["gate_arrival_scheduled"])
     if row.get("gate_arrival_actual"):
+        # Unlike departure, AirTrail hard-rejects an arrival date with no
+        # arrivalTime ("Cannot have arrival date without time") rather than
+        # silently dropping it - this pairing is not optional.
         payload["arrival"] = row["gate_arrival_actual"]
+        payload["arrivalTime"] = _hhmm(row["gate_arrival_actual"])
     if row.get("takeoff_actual"):
         payload["takeoffActual"] = row["takeoff_actual"]
+        payload["takeoffActualTime"] = _hhmm(row["takeoff_actual"])
     if row.get("landing_actual"):
         payload["landingActual"] = row["landing_actual"]
+        payload["landingActualTime"] = _hhmm(row["landing_actual"])
 
     coordinates = row.get("track_coordinates")
     if coordinates: