In even the gloomiest, stuffiest and most secluded of rooms, television can be a pocket of outdoors. With a program like public TV's "A Place of Dreams," produced through WETA-TV by Peter S. Vogt, it can also bring an invigorating whiff of stratosphere.

The hour, a filmed, annotated tour of the Smithsonian Institution's phenomenally popular National Air and Space Museum, tonight at 8 on Channel 26, maintains an unquestioningly reverential approach to the museum, as respectful as all get-out. But every now and then one gets a hint of the sensation that the building makes such a lively monument to : flight, the great liberator.

It isn't just the old newsreel footage of barnstormers' loop-de-loops that communicates the romance of flying on the program-in point of fact, there isn't enough flight footage-but also reminiscence by such affable old-timers as Smithosnian historian emeritus Paul Garber, who demonstrates with four pencils in his hand the reason the Wright Brother will never be forgotten, not even when the Eastern Suttle goes from Laguardia to Venus.

And later, Garber recalls asking Charles A. Lindbergh if the Smithsonian could have the Spirit of St. Louis for its permanent collection. Lindbergh arrived unexpectedly at Bolling Field in the plane one day, Garber says, and told him, "Well, here it is." And there it was, and there it still remains.

Unfortunately Vogt and writer Harry Miles Muheim exhibit typical TV distrust of fascinating subjects and camera naturals like Garber; the piece is over-written and burdened with a celebrity host, Cliff Robertson, who himself notes that he is "actor, writer and director," right after gushing of the museum, "Magnificent, just manigicent! That's the only way to describe this place...What a place."

He's so sepulchral he makes Orson Welles sound unpretentious. Vogt didn't trust us to grasp the obvious from what is shown; he had to smother us with words as well. Despite this all too familiar tendency, the hour has much of interest and amazement, and among the other kicks it calls is the once regular ritual of rising early in the morning to catch Walter Cronkite launching the latest U.S. rocket-to the moon perhaps, or in orbit around the earth. "A Place of Dreams" wisely evokes the dreams as well as the place.