THE importance of ``1000 Airplanes on the Roof,'' an adventurous new music-theater work, goes beyond its theme or the specific merits of its production: It represents a major infusion of energy into a practice that was vigorous a few years ago but has been flagging recently - collaboration among major figures in the more progressive branches of the creative world. It would be hard to find three more inventive personalities than the ones who assembled this show: playwright David Henry Hwang, composer Philip Glass, and designer Jerome Sirlin.
It shows the continuing vitality of multimedia spectacle as an alternative to traditional music-theater and opera. ``1000 Airplanes on the Roof'' is not exactly a Broadway-style musical, a conventional play, or a grand opera. Rather, it combines elements of all three into a new and audacious mixture.
And it's portable. All its elements - its one-person cast, its use of slide projections for scenery, and its music for a small ensemble - allow it to be moved easily from one venue to another. This makes it accessible to a wide and geographically diverse audience.
Naturally, the producers are taking advantage of that last fact. After starting its career in Austria, West Berlin, and Australia, the show played many American cities before arriving in New York, where I saw it recently. Nine more engagements are still to come.
Practical matters aside, ``1000 Airplanes on the Roof'' is an engaging show, if not a very scintillating one. In the spirit of ``Einstein on the Beach,'' which also featured music by Mr. Glass, it's a science-fiction excursion with more interest in mood than in logic. The single onstage character, known as M, is a young New Yorker who finds himself kidnaped by aliens from another planet - or possibly from his own imagination, since it's never certain whether we're watching a ``real'' story or the fantasy of a mixed-up personality. Speaking a nonstop monologue, M guides us through the events of his strange adventure, taking us from city sidewalks to a final leap into the cosmos itself.
Talk about weird science! The story of ``1000 Airplanes on the Roof'' could have been lifted from a comic book, or maybe the sort of tabloid newspaper you see at the supermarket checkout counter. Even the show's flamboyant title - it's how M describes an unearthly sound he hears - does nothing to discourage that impression. Nor does the script by the award-winning Mr. Hwang go far beyond the comic-book level of inspiration. There's a tantalizing ambiguity in the story's refusal to say for sure whether our hero (played by Patrick O'Connell) is truly the adventurer he thinks he is, but his exploits have few major surprises to spring on us.
Glass's music is more exciting than the story itself, if only because it's written for (and performed by) his own ensemble, recapturing some of the bite and urgency of such earlier Glass pieces as ``Dance'' and the ``Einstein'' score. Although its personnel has undergone some changes through the years, the Philip Glass Ensemble remains an energetic and virtuosic group with a deep-rooted sensitivity to the minimalist idiom that Glass helped pioneer. Its members currently include such veterans as Jon Gibson, Jack Kripl, and Richard E. Peck Jr., all woodwind players, and Kurt Munkacsi, who produces and engineers the ensemble's amplified music.
Also worthy of applause are the scenic designs by Mr. Sirlin, a veteran of many theater, dance, opera, and film projects. His sophisticated use of slide projection conveys a variety of moods - from poignancy to wry humor - as well as visual ingenuity for its own sake.
One wishes Sirlin and Glass would embark on a purely intuitive extravaganza of their own - on the order of ``Einstein on the Beach,'' perhaps, which felt no need for a conventional plot - that would soar on musical and visual wings far beyond the twists of this ultimately unexciting tale.
Still coming in the show's wide-ranging tour are engagements in Pittsburgh and Easton, Pa.; Minneapolis; Bloomington, Ind.; Princeton, N.J.; Hanover, N.H.; Durham, N.C.; Richmond, Va.; and Toronto, Canada, wrapping up the schedule Feb. 27-28.