I grew up in Geneva and my father has lived there over 50 years.

I have obviously flown in (and occasionally connected there) to GVA frequently.

I agree with posters above that passport control for transfers should be doable, but if you are in Y you should try to avoid being in the back of the plane.

A couple of notes:

1. Your UA flight ex-EWR will almost certainly be landing at the "bunker" which is to the north of the main terminal building. Although GVA is actually quite small it's quite a hike to passport control...this alone could take 10 minutes.

2. Your LX Departure to PMI could depart out of one of the three "pods" or the terminal extension to the south (more likely). Again, although the airport is quite small, this is at the opposite end from the bunker and is also quite the hike, as much as another 10 minutes at a brick pace.

Otherwise, passport control should be manageable, although I would not second an above comment about "Swiss efficiency," which is is painfully short supply at GVA...