I have no idea about code 1501. Call 1800MYDELTA to ask about that code. Res would not know since they do not provide support for TravelNet.TravelNet is the preferred booking method for these tickets, but Res can book Fly Confirmed for Less tickets for you. Provide them with your PPR number up front at the beginning of the call.Mileage cannot be used to pay for these tickets. Award seats are a set rate (low, mid, peak) between cities. It does not matter what the fare is between cities.