第二次onsite面试, sounds like they like you very much

They do this only in following three cases:
1. They have too much $$ to spend, so they book ticket for every candidate and the spouse;
2. Not many people want that job, so they have to spend $$ to invite people to go to their place;

3. They really like you.

Since above 1,2 may not be the true, then #3 can be the reason.
Enjoy the trip!