Hmm, you don't mean a latching air switch, but a latching relay, right?
About the only one that comes to mind is a "wishbone" type latching momentary driven relay. It combined a couple of micro-switches, with a wishbone type apperatus that would keep one micro-switch closed while keeping the opposite open. Each time the coil was energized, one micro-switch would latch open and the other would latch close. The "wishbone" was pushed by a steel rod by a momentery driven coil. You wouldn't want to energize the coil on this relay for more than a fraction of a second for it to move the wishbone. It looks kinda funky, but works reasonably well.
Dang, this is hard to describe... wish I had a pic
can anyone tell me how a latching relay works?
