New research from a UCI economist suggests that Southwest Airlines exploits its low-cost reputation with last-minute travelers who feel they don’t have time to shop around. In a survey of ticket prices for 238 routes, economist Volodymyr Bilotkach found that the cheapest last-minute fares on averaged $34.46 — 8.5 percent — less than comparable deals available through Southwest, which is known for its low prices. Southwest sells most of its tickets online but does not make its fares available via major online travel agents such as Orbtiz or Travelocity, which allow customers to compare prices.