An air-to-air coupling usable as part of a probe-and-drogue system for releasably connecting in mid-air a first aircraft, on which the coupling is mounted, to a second aircraft, the coupling comprising: one or more retaining members (19, 27) movable between a holding position in which they can interact with a suitably shaped further member, mounted on the second aircraft, to hold the further member in a predetermined position relative to the coupling and a release position in which the retaining members permit the further member to move past them; one or more sensors arranged to detect the presence of said further member; and a drive system (21, 23) which is: (a) responsive to a latching signal generated in response to detection by the one or more sensors that said further member is in a first position in which it has approached but has not reached the predetermined position, to urge the one or more retaining members (19, 27) along a path of movement from the release position towards the holding position, the path of movement including an intermediate position at which the one or more retaining members can interact withasaid further member that is in the first position, and further movement of the one or more retaining members along the said path from the intermediate position towards the holding position will tend to drive said further member that the one or more retaining members have interacted with towards the predetermined position; and (b) responsive to a release signal to permit the one or more retaining members (19, 27) to move from the holding position towards the release position or to urge the one or more retaining members from the holding position towards the release position. one or more retaining members (19, 27) movable between a holding position in which they can interact with a suitably shaped further member, mounted on the second aircraft, to hold the further member in a predetermined position relative to the coupling and a release position in which the retaining members permit the further member to move past them; one or more sensors arranged to detect the presence of said further member; and a drive system (21, 23) which is: (a) responsive to a latching signal generated in response to detection by the one or more sensors that said further member is in a first position in which it has approached but has not reached the predetermined position, to urge the one or more retaining members (19, 27) along a path of movement from the release position towards the holding position, the path of movement including an intermediate position at which the one or more retaining members can interact withasaid further member that is in the first position, and further movement of the one or more retaining members along the said path from the intermediate position towards the holding position will tend to drive said further member that the one or more retaining members have interacted with towards the predetermined position; and (b) responsive to a release signal to permit the one or more retaining members (19, 27) to move from the holding position towards the release position or to urge the one or more retaining members from the holding position towards the release position. (a) responsive to a latching signal generated in response to detection by the one or more sensors that said further member is in a first position in which it has approached but has not reached the predetermined position, to urge the one or more retaining members (19, 27) along a path of movement from the release position towards the holding position, the path of movement including an intermediate position at which the one or more retaining members can interact withasaid further member that is in the first position, and further movement of the one or more retaining members along the said path from the intermediate position towards the holding position will tend to drive said further member that the one or more retaining members have interacted with towards the predetermined position; and (b) responsive to a release signal to permit the one or more retaining members (19, 27) to move from the holding position towards the release position or to urge the one or more retaining members from the holding position towards the release position.