An unmanned aerial vehicle (UAV; 400) comprising: a tether (402, 502) disposed on a spool; a motor arranged in the UAV, wherein operating the motor in a first mode and a second mode respectively counters and assists unwinding of the tether due to gravity; a payload coupling apparatus (412, 800) structured to mechanically couple the tether to a payload (408, 510); a payload latch (406, 570, 572) switchable between a closed position that prevents the payload from being lowered from the UAV and an open position that allows the payload to be lowered from the UAV; and a control system configured to determine that the UAV is located at a pickup location and responsively operate in a payload pickup mode, wherein during operation in the payload pickup mode the control system is configured to: open the payload latch; operate the motor to unwind a predetermined length of the tether corresponding to an expected payload attachment altitude for the payload coupling apparatus; after unwinding the predetermined length of the tether and waiting for a predetermined payload attachment period, operate the motor in the first mode for a predetermined attachment verification period; determine, based at least in part on motor current during the predetermined attachment verification period, that the payload coupling apparatus is mechanically coupled to the payload; responsive to the determination that the payload coupling apparatus is mechanically coupled to the payload, operate the motor to retract the tether; while retracting the tether, determine that both: (a) an unwound length of the tether is less than a threshold length and (b) the motor current is greater than a threshold current, and responsively operate the motor to pull the payload into a receptacle on a lower surface of the UAV; and after operation of the motor to pull the payload into the receptacle, close the payload latch to secure the payload in the receptacle. a tether (402, 502) disposed on a spool; a motor arranged in the UAV, wherein operating the motor in a first mode and a second mode respectively counters and assists unwinding of the tether due to gravity; a payload coupling apparatus (412, 800) structured to mechanically couple the tether to a payload (408, 510); a payload latch (406, 570, 572) switchable between a closed position that prevents the payload from being lowered from the UAV and an open position that allows the payload to be lowered from the UAV; and a control system configured to determine that the UAV is located at a pickup location and responsively operate in a payload pickup mode, wherein during operation in the payload pickup mode the control system is configured to: open the payload latch; operate the motor to unwind a predetermined length of the tether corresponding to an expected payload attachment altitude for the payload coupling apparatus; after unwinding the predetermined length of the tether and waiting for a predetermined payload attachment period, operate the motor in the first mode for a predetermined attachment verification period; determine, based at least in part on motor current during the predetermined attachment verification period, that the payload coupling apparatus is mechanically coupled to the payload; responsive to the determination that the payload coupling apparatus is mechanically coupled to the payload, operate the motor to retract the tether; while retracting the tether, determine that both: (a) an unwound length of the tether is less than a threshold length and (b) the motor current is greater than a threshold current, and responsively operate the motor to pull the payload into a receptacle on a lower surface of the UAV; and after operation of the motor to pull the payload into the receptacle, close the payload latch to secure the payload in the receptacle. open the payload latch; operate the motor to unwind a predetermined length of the tether corresponding to an expected payload attachment altitude for the payload coupling apparatus; after unwinding the predetermined length of the tether and waiting for a predetermined payload attachment period, operate the motor in the first mode for a predetermined attachment verification period; determine, based at least in part on motor current during the predetermined attachment verification period, that the payload coupling apparatus is mechanically coupled to the payload; responsive to the determination that the payload coupling apparatus is mechanically coupled to the payload, operate the motor to retract the tether; while retracting the tether, determine that both: (a) an unwound length of the tether is less than a threshold length and (b) the motor current is greater than a threshold current, and responsively operate the motor to pull the payload into a receptacle on a lower surface of the UAV; and after operation of the motor to pull the payload into the receptacle, close the payload latch to secure the payload in the receptacle.