Could I please "borrow" this thread and seek some similar advice?

I'm booked to go with my mum from Europe to US in May.
We have the same surname, however in her passport, my mum has two surnames. It's just the first one on the ticket...
Do you guys think we will have a problem at the airport?
Our common surname is not a usual one.

We're flying Lufthansa. I've searched their website for info on name changes but seems like it only applies to group bookings!?

Please advide me on what to do?