Most "shared" *A flight?
 

I could find some codeshare flights with 4 numbers.

For example:
LH3534 between FRA-VIE is shared with NZ, OS, UA.
(as NZ4572, OS7204, UA8966)

UA890 between NRT-LAX is shared with NH, OZ, US.
(as NH7018, OZ6608, US6656)

Do anyone know any *A flight(s) with 5 numbers or more?

back when AN was around and MX was in Star NZs AKL-LAX flight had six numbers NZ/ LH/ AC/ UA / AN and MX . I think some of BDs LHR-domestic legs have huge numbers of designators ( not all of them star )

BD has been the "whore" of the alliance (and others) for years. Shares itself with so many others! AN used to be almost as bad.

Yes, I think BD is likely to come tops here, because most carriers fly to LHR and there are some onwards short-haul destinations which are not served by them, or served with limited service.
A good example on LHR-DUB would be BD 131 aka NH6885 aka OS8975 aka LH6505 aka LO4003 aka SK9775 aka JK9631 aka UA4881 aka TP8887 and also (outside *A) VS4131.

Not even close to BMI, but ARN-FRA 06:20-08:25, LH3007
Also AC9274, SK3611, SQ2107, UA9015

you may add UL 2131 for this flight - incredible!

on this route TG and (non-star) QR + EY have their code on some other BD flights, too.

Just out of curiosity - Where do I find this information?
Heathrow Live departures (this flight is scheduled to depart in 10 minutes) only shows the BD, LH and SK code. ITA only shows BD and LH. Dublin Airport timetable shows BD, LH, MH (albeit with a different arrival time) and UL.

SmilingBoy.

Skyguide shows lots of codes on most BD flights. Just checking a few examples and there are up to 8(!) codes.

LH flights FRA-ZRH (my usual route) are usually covered with a slew of codes as well. I was recently on a CRJ that carried AC, UA, NH, BD, LX and RG codes besides the usual LH.

From what I could tell, the codeshare was in some measure of demand - I noticed UA, AC and RG boarding passes among my fellow pax, and my seatmate was booked on the LX codeshare with a connecting LX flight to JNB.

skyguide was indeed where I got the info from.

Most FRA-GVA-FRA are heavily shared. This was on the GVA arrivals board for today and most of the flights had 7 or 8 "hangers-on"! All the flights are LH metal.
LH 3660
AC 9006
US 5784
QR 4803
SQ 2046
LX 3661
TG 7694
UA 9092

I seem to remember counting 13 Star partners codesharing an EDI-LHR BD flight. I'm sure bmi wins this one...

Probably stupid question
 

Hi,

This is probably a stupid question, but why do they have code-share flights?

For marketing purposes. NH or TG, for instance, do not fly to DUB. Being able to put their code on a BD LHR-DUB flight enables them to sell a ticket to DUB via LHR.
They could allow inter-lining with BD instead (i.e. sell BKK-LHR-DUB tickets where the first segment as a TG code and the second one a BD code) but that would mean less revenue for TG. Also, TG will be well known in Thailand whereas BD will not and, therefore, is likely to inspire more consumer confidence. Another reason why a codeshare can be a more attractive proposition than a non-codeshare interline.