Huh, interesting: https://flights.etihad.com/en/flights-to-st-louis
Looks like they're not direct; Flights into STL today are via a code share with American or Air Canada. http://www.etihad.com/en-us/about-us/our-partners/
Flights typically have one connection through either ORD (O'Hare Chicago), DFW (Dalas/Fort-Worth), LAX (Los Angeles), YYZ (Toronto Pearson), or IAD (Dulles). Looks like you fly into/out of one of those airports on Etihad livery bu use AA or AC planes between those airports and STL.
-RBB





