Originally Posted by
Palal
In the era of e-tickets, there may still a limit to the number of segments/coupons you can have (primarily due to the antiquated systems that GDSes use), so that may require multiple eticket numbers, although I don't think I've seen this lately.
Each ticket # still has a maximum of 4 coupons, and I believe that no more than 4 ticket #s (i.e., 16 segments) can be issued on one PNR.