WHAT NATIONAL AIRPORT is today is due in no small part to the Congress of the United States, which has watched over the gradual degradation of this whole impenetrable hub from ground approach to harried takeoffs and hair- raising landings. While it is rumored that a joint committee on airport access has been meeting for several years at an undisclosed location some miles from the baggage-loading areas, only travelers with Sherpa guides seem to be meeting or making planes with any degree of certainty these days. One might logically ask: if this is such a serious and demonstrably obvious problem -- and if members of Congress do treasure the use of a close-in airport as they keep noting -- why don't they do something about it?

The answer is that members of Congress don't readily sense this issue -- because their comings and goings are not nearly so aggravating as those of the average mortal. They can pull in and out of a free reserved-space congressional parking lot within steps of the main passenger terminal at National. There are approximately 100 spaces in this lot. No problem, right?

Wrong, according to 38 members of the House who have just concluded that something must be done about the parking situation. Accordingly, they have asked the Federal Aviation Administration to kick Supreme Court justices and diplomats out of their free parking lot to make still more room for themselves. In a letter to the FAA, the lawmakers point out that they have to cope with "irregular and unpredictable time constraints not imposed upon either members of the Supreme Court or the Diplomatic Corps."

This is an important request because it brings to light the entire scope of hideous parking and access difficulties experienced at National by the public at large. And it leads to an idea that might provide some temporary relief for everybody: Abolish all special free lots for members of Congress, of the Supreme Court and of the Diplomatic Corps. Let all public servants live like the public instead of like a privileged few. It is disgusting that Congress has created this cushy perquisite for itself and even more disgusting that its members have the gall to seek to expand it.