Originally Posted by
ckpeter
It looks like the OP will be fine.
UA and US are in the same alliance and presumably also have interline agreement, so there should not be any problem through-checking the bag. In fact, on the first segment, UA is most likely able to both through-check the bag and check the passenger in for the second US flight, despite it being on a separate reservation.
Also, the minimum connection time at LGA from UA to US is 45 minutes, so no problem with a 50 minutes connection there.
Not reality. OP points out that his wife is on separate PNR's. She's not flying two segments and checking in at ORD through to ROC with a connection at LGA. She's flying two separate itineraries. While UA and US certainly interline, that doesn't as others point out, deal with the separate PNR issue which takes a sophisticated UA agent at ORD (not an Airserv contractor) to figure out. Also, the 45 MCT for LGA is way too short given the realities of the system (mini-van between terminals). While it's a legal connection, it's tight unless one is familiar with both terminals.