DS flied home also during these two breaks (Thanksgiving and Spring Break) during college. I think we must have spent several thousands a year. But we skipped all the parent weekends. We did flied to campus at the end of the spring semester though.
Yes, we spent a lot on the traveling cost during those 4 years.
It is a totally different situation after college. (In this year, I think he will again spend more on airfare.)