Air is a progressive jazz trio whose first album, "Open Air Suit," has just been released. They're supporting their debut with a tour that brings them to District Creative Space Friday and Saturday. Their music is the unstructured form of the loft. Their compositions are dense and complex. Their rhythms are unpredictable.

I do not understand Air.

The three players are Fred Hopkins (bass, maracas and stick), Henry Threadgill (tenor, alto and baritone saxophone and flute), and Steve McCall (drums and percussion). The three appeared as Air as early as 1976. Hopkins was prominently featured on the "Wildflower" album series that documented loft jazz' first big festival in New York two years ago. Threadgill is the leader of Air and the composer of all four of the album's tracks. McCall has jammed around New York City and is obviously attuned to this musical genre's absence of rhythmic stability. All three men are proficient players. All three seem to be interconnecting on a level that most listeners will not attain right away, if at all. Most of the time they sound to me like a night of heavy traffic on Connecticut Avenue.

Which is not to say that "Open Air Suit" is a bad album. I really don't know what constitutes "bad" when the object of the pieces is to be as free-form as possible. Since it usually sounds as if the musicians are playing three different tunes simultaneously, there's no way to get a handle on just what to listen for or compare it to. Which is the idea, of course.

The "loft jazz" style began to take hold in 1976 when saxophonist Sam Rivers decided to play his own way in his own studio, the Studio Rivbea in New York. Anyone who wanted to jam was invited, and soon listeners had to pay a small admission to watch the players work out. The music produced was similar to the "free jazz" of Ornette Coleman. Some called it "dynamic" and hailed it as "one of the most important musical developments of the '70s." Others called it "noise."

After all, you couldn't dance to it, you couldn't hum the tune, you couldn't tap your foot or snap your fingers to the beat. Most times, you couldn't listen to it for more than 10 minutes without being converted to Andre Kostelanetz.

Despite a lot of press, pro and con, "loft jazz" never has gained commercial acceptance. Practitioners like Oliver Lake, Stanley Cowell and Hamiet Bluiett sell relatively few albums and a Washington "new music" festival scheduled last Thanksgiving weekend fell apart primarily from public apathy.

D.C. Creative Space is the only club in this area that will book an act like Air (Sam Rivers will appear there later this month), but its clientele - though loyal - is not nearly large enough to support a whole movement. And so the movement continues without much popular support and with critics like me stumbling through tracks titled "The Jick or Mandrill's Cosmic Ass," trying to find something intelligent to say.

In all fairness, it should be pointed out that the first half of the first cut on "Open Air Suit" starts off with a reasonable facsimile of steady rhythm before going into orbit. And track four (the title can't be printed in normal type) is tempered by Threadgills lyrical flute. Also to be noted is an off-putting pretentiousness in liner notes like "Whereby from a customed viewpoint Air was considered, however it was conceived as something that Air would have to fit itself up to or rather into."

Something more to consider. Despite the fact that a lot of people do not think works like "Open Air Suit" are music, Air's form of expression is here to stay. Their album is one of several issues on the Arista Novus label (which has apparently replaced Arista Freedom) that showcase loft-type jazz. Every day, new experimental efforts are released and the audience for them is growing, excruciatingly slowly but surely.

And remember (as critics always must): plenty of people did not think Elvis Presley was music. Or Arnold Schoenberg. Or Miles Davis. Or the Beatles.

With that in mind, listen to Air. See them perform. Decide for yourself.

OPEN AIR SUIT - Arista Novus, AN 3002. DISTRICT CREATIVE SPACE - Seventh and E Streets NW, 8 and 10, Friday and Saturday