The DMN‘s Terry Maxon explains the switch:
More than a year ago, officials announced that it would rename the carrier, owned by American Airlines Group, because it wanted to use the American Eagle brand on all its regional flying.
In the past, American Eagle referred to American Eagle Airlines and Executive Airlines, the two regional carriers owned by American Airlines Group. Regional flying done by non-owned carriers was branded as American Connection.
But American Airlines has added American Eagle service from SkyWest and Republic Airlines in the past two years, and decided in late 2012 to rename American Eagle Airlines to something else. The Dec. 9, 2013, merger with US Airways brought two US Airways Express carriers into the family, and they’ll be rebranded as American Eagle over time.
The renamed Envoy will still fly for American Airlines under the American Eagle brand, of course, even if it isn’t American Eagle Airlines.
I don’t know how anything gets done over there.