In short term, travelers will no no major differences. One can still use the same procedure at the airport with either ticket as you did in the past. Frequent Flier mileage will be saved from both companies and kept in a database for the new company. The new American Airlines will be part of the Oneworld Alliance. US Airways will leave the Star Alliance.
The long term affect could indeed could cause problems in an areas we all fear, Price! Chances are though that these increases probably will be felt in smaller cities due to lack of competition. Still those who found comfort in both companies may now be forced to compromise on some issues.
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