US Airways responds:

[jwgh]

Here's what they say:

It appears your email address has changed. If we should use this new address, please update your contact information here.

I click on the link and it asks for my email address. I type in my email address and am informed:

Login Failed
The login ID and password combination you provided is invalid.
If you believe you may have mistyped either value, use the browser Back button to return to the login page and try again.

If you believe you have forgotten your password, use the browser Back button to return to the login page and request that your password be emailed to you.

Of course the original screen didn't ask for a password and also it doesn't have any instructions for getting the password emailed to me.

I typed in a different email address and it worked. This is pretty outstanding.