I don't think airport security would be happy if you tried to transport sodium chlorite into the passenger cabin, even if you limit the amount to 3 ounces or less. An accidental spill could fill the cabin with chlorine dioxide gas, or start a fire.
If you put it into your luggage, there are no restrictions if the concentration is 50000 PPM or less as long as it is properly packaged to contain any spilling that may occur due to pressure changes during the flight. Industrial strength concentrations like Miracle-Mineral-Supplement with its 280000 PPM concentration need to be declared as hazardous goods, be properly labeled as an oxidizer, be properly packaged, and be accompanied by an accurate MSDS.