IslamQA: Is there a difference between wearing hijab and abaya or loose shirts and pants?

Is there any difference if one wears hijab and casual clothing (long sleeve loose shirt and loose pants) to the one who wears hijab and an abaya?

Different scholars will likely have different opinions on that. My view is that as long as the purpose of the hijab is achieved and the hair and body are covered (save for the face, hands and according to some scholars, the feet), then type of dress does not matter. The point is for a Muslim woman to dress in a way that prevents lecherous men from having anything erotically satisfying to look at, and this can be achieved through all kinds of costumes.