Your rules: Direct only; 20 kg checked bag each way; land within 3 hours of each other; out Friday night or Saturday morning, back Sunday; traveller B won't fly from Hong Kong.
Sample data. Fares and times are real (Google Flights via SerpApi, checked 11 Oct 2026). Bag fees are placeholders until the fee table is built.
Best option
Sample data
Shanghai
4–13 Dec, landing Sat 5 Dec. All times are Shanghai time.
A from SIN, 06:30B from SZX, 07:302h waitB lands 09:45A lands 11:4506:0007:0008:0009:0010:0011:0012:0013:0014:00
Traveller A on 9C 8552 leaves SIN at 06:30 and lands at PVG at 11:45, Sat 5 Dec, Shanghai time.
Traveller B on MU 5332 leaves SZX at 07:30 and lands at PVG at 09:45, Sat 5 Dec, Shanghai time.
S$908–986for bothEstimated
Traveller B lands first and waits 2h at PVG.
Shanghai, 4–13 Dec: who pays what
Traveller A, from Singapore
S$639–691
Fares S$563, checked bags S$76–128* (placeholder bag fees)
Out9C 8552, SIN–PVG, Sat 5 Dec, 06:30–11:45S$400 fare, S$38–64 bag* (placeholder)Fair. Within the typical S$240–405
Back9C 8551, PVG–SIN, Sun 13 Dec, 23:30–05:30S$163 fare, S$38–64 bag* (placeholder)Good. Low end of the typical S$140–375
Traveller B, from Shenzhen
S$269–295
Fares S$231, checked bags S$38–64* (placeholder bag fees)
OutMU 5332, SZX–PVG, Sat 5 Dec, 07:30–09:45S$131 fare, S$0 bag* (placeholder)Fair. Within the typical S$85–135
Back9C 8917, SHA–SZX, Sun 13 Dec, 07:30–10:10S$100 fare, S$38–64 bag* (placeholder)Good. Low end of the typical S$85–135
To Traveller A in Singapore and Traveller B in Shenzhen
Together S$908–986
Land 2h apart
Google Flights fare plus a bag fee from our table. Not yet checked with the seller.
* Bag fees are placeholders until the fee table is built.
Out flights 9C 8552 and MU 5332
Postcard shows Shanghai, 4–13 Dec, front.
Every city and window
City
4–13 Dec
11–20 Dec
Shanghai
Seoul
Osaka
Tokyo
None meet your rules
None meet your rules
Cheapest group total in each. All are Estimated and include placeholder bag fees.
All 14 options, cheapest first
Bring a city back
Allow Friday departures from 17:00
Brings back Tokyo (4–13 Dec)S$1,833–1,885 for bothLand 2h 40m apart
Brings back Tokyo (11–20 Dec)S$2,076–2,128 for bothLand 2h 40m apart
Totals include placeholder bag fees. Your rules stay as they are until you change them.