Business people go all over, including downtown. People in the downtown area on business have more convenient and faster ways of getting to the airport. The rail system is not suited for travelers with luggage. The Airport light rail system would require transfers, from whatever takes you to the rail line. Trips to the airport depart after the Gateway station.
Plans are to run one train out of every three to the airport and the other two to Gresham.
Two thirds of Downtown borders will either have to wait for an airport train downtown or wait and transfer at Gateway. The rail trip would be slower than alternatives because alternatives are door to door. Both pleasure and business nonresidents rent cars so they can tour the region on their visit. Summary A light rail line would be very expensive to operate. Based on results with such service everywhere, the fare recovery ratio would be very low.