the only thing that you have is two wings travelling at different speeds but describing the same horizontal path, so there AOA must be the same
AOA remains the same for each wing.
If the AOA was not constant during the turn there would be a constant rolling motion to the inside of the turn
For a constant Angle of Bank the Lift generated by each wing must be the same. In a turn the outer wing will be traveling through the air fractionally faster than the inner wing, therefore the inner wing must have a higher Angle of Attack than the outer wing.
Here's one for the Boffins:
In order for an aircraft in a steady, banked, level turn to the left to maintain a constant flying attitude (as seen out of the front windscreen) it MUST, by definition, be continuously Yawing to the left, Rolling to the right and Pitching up.
Discuss...........