I saw the '89 reunion in Detroit, and they did bring it.  Original drummer Spencer Dryden elected to not join the tour, due, I believe to bad health at the time.  He was replaced by one of rock's current great session drummers, Kenny Aaronoff (John Mellencamp, Melissa Etheridge, Iggy Pop, etc.).  I remember it to be a very tight show, with beautiful harmonies, and all the hits, interspersed with stuff from their then new album ("Planes?").  I very much wish Grace would reconsider.  Such a volume of incredible music and messages to be heared by new generations of listeners who missed an era of music due to corporate radio ownership, and new artists having no forum (except for the internet) to get their music heard by the masses.  I've caught some of the regrouped Kantner/Balin/Aguilar recent live shows, and they are tough with poor sound quality and sometimes wildly off harmonies. 

Completely agree on Airplane vs. Starship. Different animals, but the former just has so much more of a diverse and high quality body of work.  I always thought a great performer who could fill Grace's spot would be Johnette Napolitano of Concrete Blonde.  Tremendous singer/songwriter in her own right, with Grace's same anger and anti-establishment spirit.  Check out their work if you haven't already.