Is it possible to have 2 or more roundtrip flights assigned to each aircraft per day? (i.e Aircraft would fly to A-B-A during the day and A-C-A at night) without encountering problems in scheduling flights? Thanks.
Yes, It is. Try not to exceed 24 hours or you will have to reschedule new routes in the remaining time.
You should have all flights in a single route, like this:
Having two separate routes, assigned to the same aircraft, only works if the routes fly on different days.