Noel Coward once wondered, "Why do the wrong people travel, and the right people stay at home?" Once there were right ways to travel, however -- the Broadway Limited, the Orient Express and the luxury liners that crossed the North Atlantic.

Like so many eras, this one has ended, but it is commemorated tonight with a National Georgraphic Special, "The Superliners: Twilight of an Era," produced for PBS and shown at 8 on Channel 26. Like the late, great ships it celebrates, this is a superior piece of transportation.

In their day, ships like the Normandie, the Queen Mary and the France were "the largest moving objects made by men," and may remain the most mammoth carriers of human cargo in history until the day when space arks carry masses to the stars, according to the script by producer-director Nicolas Noxon.

The hour allows for glimpses, not always generous enough of the liners in their prime, outfitted with opulence, plush with amenities and designed for a world that still had time to savor graciousness. It was all done in by technological efficieny: the jet plane, which made getting there the sole, object, and the whole concept of enjoying the trip a sacrificial frill.

Unfortunately, Noxon keeps cutting back and forth between the priceless newsreel footage and scenes of the 296th crossing of the Queen Elizabeth 2, considered the last of the luxury liners. The QE2 footage might better have been organized as a framing device for the beginning and end of the program; perhaps Noxon thought viewers would get jumpy if exposed to to much black-and-white at a time.

If so, it is egregious commercial thinking, but then the Geographic Specials are made to be sold into commercial syndication after their PBS exposure; hence the unnecessary padding of an introduction from E. G. Marshall. Marshall takes up space that will one day be filled with ads.

Nevertheless, much of the QE2 footage is very good, especially a montage of life aboard ship -- above and below decks -- near the top of the hour, and comments from employes of the Cunard Line, including the captain of the ship, who seem to realize that even this beauty's days are numbered.

Executive chef John Bainbridge not only talks about the rigors of preparing vast amounts of food at sea, but also tells a touching story about how his wife put her foot down one day and threatened to leave him if he went off to sea again." I went," he says simply, "and my wife and I parted." Thus is the QE2 a floating refuge for romanticism of one kind or another.

But the excess of QE2 film makes the special seem practically a travel poster. More fascinating are films of the old ships -- the Queen Elizabeth sneaking out of Scotland to New York in 1940 to avoid the war, the Queen Mary carrying more than 16,000 troops after converstion to the war effort in 1943, or the Normandie, seen under construction, in full glory at sea, and then suffering the indelible ignominy of burning and capsizing while docked in New York.

"Twilight of an Era" is probably an optimistic title, since the era has long since ended. Perhaps "Twilight Zone of an Era" would have been better. Even with its flaws, however, this is an uncommonly scenic cruise.

A couple of words should be said about the narratora, Alexander Scourby: absolutely impeccable. Since at least the mid-'50s days of NBC's "Project XX," Scourby's voice has been a rich and authoritative one on documentaries and a few commercials ("Because the wine remembers. . . .") He's still the best at what he does.