Originally Posted by
jorun
if the airlines don't have IA you can't mix them. You can mix them only if there is a third airline which has IA with the others. It's a smart way to force the ota to issue the ticket on another stock.
Anyway most of the dump are between airlines with IA.
it's better to focus the attention on which stock dumps the airline XX. There is a tool which can tell you exactly if airline XX is dumpable by stock XX. Sometimes fare rules tell you exactly which stock dump airline XX.
This is not 100% correct.
It's up to which reservation system is used by OTA !
Some require that every involved airline in a ticket need IA with each other. If have 3 different airlines in PNR A needs with B, A needs with C, and B needs with C. And special case if tix should be issued on a 4.th airline which is not flying, them also need IA with this one. Aditionaly it may be neccesarry that ticketing FR's confirm on which airline(s) the tix may be issued.
Other reservationsystem requires in same example only IA between issuing carrier and each other involved airline. So if tix is issued on A, IA is only needed between A and B and between A and C. But
not between B and C !
But there are some more factors, if tix can be combined, which may be found in FR's, but some in special cases need a manual proof over an extern website.