Oxone flux has been measured from aircraft by the eddy correlation technique over the Gulf of Mexico, the north Pacific Ocean, and a Gulf Coast pine forest. Measurements over the Gulf were obtained in polluted air (which had flowed down the Mississippi valley) over relatively warm water, while the north Pacific observations were obtained in pristine air over relatively cold water with nearly neutral stratification. Values of the surface resistance to ozone were about 1.8¿103 s m-1 over both ocean surface and 40 s m-1 over the forest, with an accuracy of better than ¿15%. Photochemical production of ozone during midmorning with clear skies over the Gulf of Mexico was 0.2--0.3 ng m-3 s-1, which is an order of magnitude less than that observed over northeastern Colorado.