I will depart from IAD next sunday late evening and was wondering how early I can check in for my flight back to Europe.

I will stay with friends near the airport and would like to drop off bags and the rental car and then head out with them for dinner returning about an hour before scheduled departure to get to the gate. I think to remember that you can check-in six hour ahead, but this information is at least five years old.

So has anyone a current first-hand experience how early you can checkin with UA (if it's important - I'll be on UA924 to LHR departing at 9:30p)? Any help would be greatly appreciated!

Greetings - Dirk