Well, I'd call it more of a "gagging" noise, but I get what you mean. Typically, that's what's going on. A heaving of the abdomen is usually associated... all in all, pretty disgusting, but then I'm not a cat aficianado. Mrs. C is, though and in the winter she keeps a little pot of growing wheat grass that is obtained from the pet supply store for her little Persian to nibble on. It seems to help. I notice, in the summer, the cat eats the ends of tall grass outside and then does the heaving routine soon after, bringing up the little "gift"... If left to my own devices, the cat fully understands the true meaning of "airborne"... at least for the few feet to get her from the door to the edge of the patio...