The 737-800 and 777 achieved higher payrates relative to weight and speed then other equipment on the property at Delta via the 3B6 process. They were new aircraft. DALPA took the position that since these were new very efficient aircraft both from a fuel and crew standpoint (3man to 2 man) that they should be paid accordingly. DALPA was able at the time able to negotiate industry leading rates on both aircraft out side the normal contract negotiations. THese rates directly lead to the UAL contract and follow on Delta contract in 2001. Since the rates were negotated as new equipment within the 3b6 contract section the other aircraft were not up for rate changes. There has been some equalization in the rates in follow on contracts but they still pay a premium relative to other equipment.