The Mississippi River is known as the Middle Mississippi from the Upper Mississippi River's confluence with the Missouri River at St. Louis, Missouri, for 190 miles (310 km) to its confluence with the Ohio River at Cairo, Illinois. The Middle Mississippi is relatively free-flowing.
As Hopper notes, eight major U.S. airlines offer free cancellation for tickets purchased at least seven days in advance: Delta, United, US Airways, JetBlue, Southwest, Spirit, Frontier and American (in American 's case, you'll hold your ticket instead of purchasing it).
This likely will not impact most travelers (who donât cancel their flights) â but donât forget to cancel your Southwest Wanna Get Away or Ding! ticket at least 10 minutes before departure if you donât plan on flying. You wonât get a credit for the price of your ticket if you donât! Southwest Has A New No-Show Policy.