United Airlines has installed touchless baggage check-in technology in all 219 of the U.S. airports in which the carrier owns kiosks. The technology enables travelers to print bag tags by scanning a mobile or printed boarding pass without needing to touch a screen. United developed the technology in 30 days and installed the first stations on May 10 in Boston, Orlando, Chicago O'Hare and Dallas-Fort Worth. The carrier will continue adding more stations in U.S. and international airports though July.