United Airlines will use an antimicrobial coating product across its full fleet by the end of the year, the carrier announced. The carrier currently is using Zoono Microbe Shield, which bonds to surfaces and creates a protective layer that can burst cell walls and membranes of microbes, on high-touch areas of more than 30 aircraft at its Chicago O'Hare International Airport hub. That will be expanded across all mainline and express aircraft over the next few months. The U.S. Environment Protection Agency classifies the product at Category IV, the lowest level of toxicity, according to United.