THE U.S. TRAVEL SERVICE, no doubt, does some interesting and useful things. It encourages those who live in other countries to visit the United States and provides them with information and aid in planning their trips. It doesn't spend much money as government agencies go -- less than $10 million a year -- and it has a host of friends, most of them travel agents. How odd that this little organizational preserve is caught up in a controversy between Congress and the administration.

Congress would evidently like to set up the travel service as an independent agency -- it's not a part of the Commerce Department. The administration would like to fold its operations into that department's International Trade Administration. As a "compromise," a House committee last week proposed keeping the travel service in Commerce but upgrading it to an "administration," promoting its chief from assistant secretary fo undersecretary and authorizing the service to open nine new offices. There is talk now of a presidential veto.

All this pulling and hauling is going on, mind you, over an operation on which the House committee wants to spend a measly $7.6 million in 1982.

We have a better idea. Why have a federal travel agency at all? Sure, it's a nice thing to have. A lot of governments have one these days, even a money-pinching state government like that of Virginia. But in this day of looking for governmental functions to turn back to private hands, should the travel business be exempted? Promotion abroad of this country's attractions is desirable and useful. But so are cheap school lunches, additional park land and Social Security cost-of-living increases.

Instead of talking about where to put the travel service, Congress and the administration should start talkaing about why there is one. Is it possible that David Stockman overlooked something?