Headphones or earbuds? The former have considerably more space in which to put an antenna that extends past the side of the wearer's head; earbuds have a pretty strict limitation in this regard, and indeed all the ones I've tried (ranging in price from about $10 to about $60) have at least occasionally dropped signal with the phone in my front trouser pocket on the same side as the earbud. For AirPods never to do so would be a significant differentiator in my experience.