I remember Senator Feinstein groveling, but I remember that Bush said we were sorry for the death of their pilot as we would be for anyone, but we never apologized or took responsibility for the midair collision.
I specifically remember Chinese commentators being angry that one Chinese word used in the official translation meant sorrow but was not the one that meant regret with nuance of personal responsibility that they wanted.
Either way, it was an apology and not just an expression of regret over the death of Wang Wei.