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).
Southwest now requires that you cancel or change a ticket prior to the flight departing. This is a new-ish rule for Southwest and you must cancel/change at least 10 minutes prior to take off. If you donât Southwest will not credit you back the amount/points if you miss your flight.I still think this is a VERY reasonable policy as changes/cancelations can still take place day of departure for no fee!ompared to all the other US airlines, Southwest has the best change/cancelation policy out of them all. While I know many people are anti-Southwest, their flexibility with changing and canceling flights really makes them a winner in my opinion.