So my last employer used Concur which was actually just the front end for AMEX Business travel. However, I just switched employers and they use Navan (formerly Trip Actions). They're a much smaller company. I am able to use my own credit card or book through their centrally billed one. The flights post on my credit card as "American Airlines". However, I'm not booking through the AA web site. Any idea how this is considered? Fortunately, the travel policy does allow me to book directly outside of the tool, but the tool is highly encouraged to enforce compliance.