(Portland, OR)  --  Portland International Airport will require all travelers to wear face coverings starting May 18th.  Children under age two and people with medical conditions that prevent face coverings are exempt.  Port of Portland Chief Operating Officer Dan Pippinger says it's an important step to restore trust in the travel process.  The meeter-and-greeter areas are also closed.  They're asking groups that want to meet a traveler to do it at home.