Southwest Airlines, for example, will begin just four, all of which will take off this week. These Southwest Routes Begin This WeekThe following four links were all revealed last November. Southwest has only operated one of the four routes before, which is LGB to Portland International Airport (PDX). That was despite nonstop flights to PDX being available from Hollywood Burbank Airport (BUR), Los Angeles International Airport (LAX), Ontario International Airport (ONT), and John Wayne Airport (SNA). Harry Reid International Airport (LAS), serving Las Vegas, is second (459 daily), followed by Chicago Midway International Airport (MDW; 422 daily).