From Renmin daxue to Beijing Capital Airport with Airport Shuttle Bus

Hello,

can anyone advise me whether the line 4 (Gongzhufen) leaves as early as 4:30 or 5 a.m. from the station Friendship Hotel to the airport?
Another important question: Can I use my blue public transportation card (the one you use for the subway) to pay the transportation fee, is cash also possible?

Thank you for the reply in advance!

Best,