diff --git a/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx b/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx
index ddd614c2b..6c580622b 100644
--- a/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx
+++ b/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx
@@ -12,6 +12,7 @@ import { parseReservationMetadata } from '../../utils/flightLegs'
 import { BookingDialogHeader } from './bookings/BookingDialogShell'
 import { BOX, Eyebrow, Field, fs, toneColor, toneOf } from './bookings/bookingParts'
 import { filesFor } from '../../utils/reservationFiles'
+import { bookingDayLabel, segmentCodeLabel } from './transportDetailModel'
 import { TransitLegs, transitSummary } from './bookings/transitParts'
 import type { Reservation } from '../../types'
 
@@ -185,8 +186,7 @@ function detailCells(res: Reservation, meta: Record<string, unknown>, t: Transla
   if (legs.length > 1) {
     for (const leg of legs) {
       if (!leg?.confirmation_number) continue
-      const segment = [leg.from, leg.to].filter(Boolean).join(' → ')
-      add(segment || t('reservations.confirmationCode'), leg.confirmation_number, true)
+      add(segmentCodeLabel(leg, t), leg.confirmation_number, true)
     }
   }
   return cells
@@ -196,9 +196,7 @@ function detailCells(res: Reservation, meta: Record<string, unknown>, t: Transla
 function whenOf(res: Reservation, locale: string, timeFormat: string): { day: string; time: string } {
   const { date, time } = splitReservationDateTime(res.reservation_time)
   const { time: endTime } = splitReservationDateTime(res.reservation_end_time)
-  const day = date
-    ? new Date(date + 'T00:00:00Z').toLocaleDateString(locale, { weekday: 'short', day: 'numeric', month: 'short', timeZone: 'UTC' })
-    : ''
+  const day = date ? bookingDayLabel(date, locale) : ''
   const start = time ? formatTime(time, locale, timeFormat) : ''
   const end = endTime ? formatTime(endTime, locale, timeFormat) : ''
   return { day, time: start && end ? `${start} → ${end}` : start }
diff --git a/client/src/components/Planner/transportDetailModel.test.ts b/client/src/components/Planner/transportDetailModel.test.ts
new file mode 100644
index 000000000..94728a6de
--- /dev/null
+++ b/client/src/components/Planner/transportDetailModel.test.ts
@@ -0,0 +1,21 @@
+// FE-PLANNER-TRANSPORTDETAIL-001 to -002: the labels the desktop transport detail
+// and the phone transport sheet both read off a booking.
+import { describe, expect, it } from 'vitest';
+
+import { bookingDayLabel, segmentCodeLabel } from './transportDetailModel';
+
+const t = (key: string) => `t:${key}`;
+
+describe('transportDetailModel', () => {
+  it('FE-PLANNER-TRANSPORTDETAIL-001: the day reads as weekday, day and month, on the calendar date itself', () => {
+    expect(bookingDayLabel('2026-07-01', 'en-US')).toBe('Wed, Jul 1');
+    expect(bookingDayLabel('2026-12-31', 'en-US')).toBe('Thu, Dec 31');
+  });
+
+  it('FE-PLANNER-TRANSPORTDETAIL-002: a segment code is listed under its route, or the plain code label', () => {
+    expect(segmentCodeLabel({ from: 'MUC', to: 'FRA' }, t)).toBe('MUC → FRA');
+    expect(segmentCodeLabel({ from: 'MUC', to: null }, t)).toBe('MUC');
+    expect(segmentCodeLabel({ to: 'FRA' }, t)).toBe('FRA');
+    expect(segmentCodeLabel({ from: null, to: '' }, t)).toBe('t:reservations.confirmationCode');
+  });
+});
diff --git a/client/src/components/Planner/transportDetailModel.ts b/client/src/components/Planner/transportDetailModel.ts
new file mode 100644
index 000000000..431962a0a
--- /dev/null
+++ b/client/src/components/Planner/transportDetailModel.ts
@@ -0,0 +1,25 @@
+type Translate = (key: string, params?: Record<string, string | number>) => string;
+
+/**
+ * What the desktop transport detail dialog and the phone transport sheet both read
+ * off a booking. The booking's files come from utils/reservationFiles.
+ */
+
+/** The day a booking runs on, as the head of either detail names it, in the locale's order ("Wed, Jul 1" in en-US). */
+export function bookingDayLabel(date: string, locale: string): string {
+  return new Date(`${date}T00:00:00Z`).toLocaleDateString(locale, {
+    weekday: 'short',
+    day: 'numeric',
+    month: 'short',
+    timeZone: 'UTC',
+  });
+}
+
+/**
+ * The name a segment's own booking code is listed under (#1943): where it leaves
+ * from and where it goes, or the plain booking code label when the segment names
+ * neither.
+ */
+export function segmentCodeLabel(leg: { from?: string | null; to?: string | null }, t: Translate): string {
+  return [leg.from, leg.to].filter(Boolean).join(' → ') || t('reservations.confirmationCode');
+}
diff --git a/client/src/mobile/screens/trip/sheets/MTransportSheet.tsx b/client/src/mobile/screens/trip/sheets/MTransportSheet.tsx
index 22c31294e..e7a40ecac 100644
--- a/client/src/mobile/screens/trip/sheets/MTransportSheet.tsx
+++ b/client/src/mobile/screens/trip/sheets/MTransportSheet.tsx
@@ -10,6 +10,7 @@ import { getFlightLegs, getTrainLegs, usesStationRoute } from '../../../../utils
 import { openFile } from '../../../../utils/fileDownload'
 import { runsOnDay } from '../../../../utils/reservationRoutes'
 import { filesFor } from '../../../../utils/reservationFiles'
+import { bookingDayLabel, segmentCodeLabel } from '../../../../components/Planner/transportDetailModel'
 import type { Reservation } from '../../../../types'
 import { Eyebrow, INNER_CLS, StatBox, TileHeader, displayTime } from './MTripSheetUi'
 
@@ -88,11 +89,7 @@ export default function MTransportSheet({ planner, shell }: MTripSheetsProps) {
   if (meta.flight_number) subParts.push(meta.flight_number)
   if (meta.train_number) subParts.push(meta.train_number)
   if (from?.name && to?.name) subParts.push(`${from.name} → ${to.name}`)
-  else if (date) {
-    subParts.push(new Date(`${date}T00:00:00Z`).toLocaleDateString(locale, {
-      weekday: 'short', day: 'numeric', month: 'short', timeZone: 'UTC',
-    }))
-  }
+  else if (date) subParts.push(bookingDayLabel(date, locale))
 
   const seat = meta.seat
   const platform = meta.platform
@@ -247,7 +244,7 @@ export default function MTransportSheet({ planner, shell }: MTripSheetsProps) {
             {legCodes.map((leg, i) => (
               <div key={i} className="flex items-center gap-2">
                 <span className="min-w-0 flex-1 truncate text-[0.71875rem] font-medium">
-                  {[leg.from, leg.to].filter(Boolean).join(' → ') || t('reservations.confirmationCode')}
+                  {segmentCodeLabel(leg, t)}
                 </span>
                 <button
                   type="button"