The corridors and waiting areas at National airport are deplorable! Think about it. This is the airport that welcomes people from all over the country to our Nation's Capital.

When a flight lands, and several hundred people trample into the terminal to meet the other hundreds who are there to greet them, they encounter not only the filthiest public areas (next to gas-station restrooms), but also the most disorganized waiting areas imaginable.

In one section near the Northwest Orient terminal, the seats in the waiting area were removed, leaving a stained carpet and cigarette butts everywhere (although there are plenty of ashtrays concealed in neat little corners and tucked away behind support beams where no one can see them). It's easier just to drop a butt on the floor and smother it with a foot, and, of course, there is no place to sit. So what do folks do when their planes are hours late? They sit on the floor -- which is littered with expelled chewing gum, candy wrappers, used airline tickets and stubs, and those nasty wads of gray and brown dust, hair and dirt, gathering in the corners.

Using the restroom there is a gut-wrenching experience. The towel holders are empty, and the toilet-paper holders in the stalls are empty. Then you check the stalls; some of these are missing locks. Lo and behold, the paper towels are there -- in a flooded commode.

Who's in charge out there? Whoever it is should take a stroll through the terminal, look at the problems and get someone to spruce up the place. Put litter cans and ashtrays where people can get to them. Install reasonably comfortable and adequate seating. Maybe there should even be a few signs encouraging people to put litter in its place. Placing a railing around the baggage-claim area would allow the general flow of traffic to continue moving. As it is, in the Northwest area, folks coming and going get lost in the sea of hundreds waiting for their bags.

Ah, yes, and then there's the parking . . . MARGARET A. FRANSEN Arlington