The only vaguely comparable grounding was when British and French authorities rightly suspended Concorde's C of A, after Paris accident. It took 14 months to lift the suspension. Boeing/FAA will get 787 back in the air faster but not as fast as some hope. BTW FAA should have suspended 787's C of A as soon as it became obvious that the plane did not meet certification requirements. It was not legally appropriate to use an AD.