In a head-to-disk stabilizing unit of a recording and/or reproducing apparatus, a flat air bearing surface surrounds an elongate opening to a negative pressure cavity. A record and/or playback head is arranged in the cavity with its transducer means (e.g., a magnetic gap) disposed at the opening in substantially coplanar relation with the air bearing surface. If a flexible magnetic disk is rotated at a relatively high speed to move successive portions of the disk over the air bearing surface, the surface will stabilize each portion of the rotated disk by damping out any flutter before a negative pressure formed in the cavity pulls the disk portion substantially into contact with the transducer means, thereby ensuring a constant and intimate transducer-to-disk magnetic coupling. The air bearing surface is disposed at a negative attack angle with respect to the rotated disk to cause the formation of a Bernoulli pull down force along such surface, which enhances disk stabilization over the surface and disk pull down at the cavity opening. In a preferred embodiment, a leading curved edge of the air bearing surface penetrates into the rotated disk to choke off the flow of moving air over the surface, to facilitate the formation of the pull down force.