According to the user’s manual, it is “A code to designate the preferred mode (method of movement) for a mobility requirement being deployed to an overseas theater.” A=Air; S=Sea; L=Land; Z= In-Place. “A” indicates movement by Air, which is the normal means for aircraft to self-deploy. Choosing another mode will affect the TPFDD delivery time for aircraft; if the mode is “Z”, the TPFDD deliveries are made at time 0, rather than RDD days after the initiating event.