I'm not completely sure what your problem is. Is it the varying forms of "American Airlines" that are the problem?
If so, then you could create a calculated field, like this:
IF LEFT([Airline],4) = 'Amer' THEN 'American Airlines'
Of course, if you ever get a new value in your data that doesn't have "Amer" at the beginning, it won't work, but hopefully that's relatively unlikely?
Alternatively, you could create a group and group those different values together as American Airlines, but that's even more vulnerable to new and different values coming into your data with a refresh.