It's probably on a manager by manager basis. If I work a weekend day on business--whether because of travel or because there's a software community event on the weekend--I can take a comp day. For nights not really. But if I get home late at night, no one's going to bat an eye if I take it easy in the morning so long as there's nothing I have to do. My time is usually pretty flexible.
Just curious... does your leadership go out of their way to offer comp time for travel outside of business hours?
For example, they say or strongly suggest that folks who have to travel at night take the next morning off.
I imagine that this may not be common, but it seems like it would generate a lot of goodwill for folks who have to travel.