THE FRIENDS of the Concorde, most notably, in Britain and France, will find some, but not much, solace in the legal brief the Department of Justice filed in New York the other day. And they undoubtedly will find it difficult to explain to the citizens of those two countries just why the U.S. government cannot do for the Concorde what it says ought to be done. For the government says, as clearly as it can, that the COncorde ought to be allowed to operate for a trial period at Kennedy Airport. But then it goes on to say that the Carter administration can't do any more than it has already done to see that the British and French get the landing rights necessary for that trial. To anyone unaccustomed to the peculiarities of a federal system of government, that result has to be almost incomprehensible.

The situation arises from the Justice Department's view that Congress has never exercised the power it possesses to give the executive branch full control over aviation. Instead, it says, that power is shared by the federal and state governments. This means that the New York Port Authority, which runs Kenedy Airport, has a legal right to require airplanes landing there to meet the noise standards it sets. And that means the fate of more than just the Concorde rests in the hands of the Port AUthority because of growing resentment abroad about the way that airplane is being treated in the United States.

There is one bit of light in this otherwise somber picture. It is the Justice Department's assertion that the Port Authority has discriminated against the Concorde. If that assertion is right - and it seems to us it is - the department says the federal courts can properly order the Port Authority to let the COncorde fly in and out of its airport. The charge of discrimination is based on the differences in the way the Port Authority has treated the application by owners of the Concorde and the way it treated the applications for other new airplanes in the past. It gave the owners of those other new planes a chance to demonstrate that the planes could meet the airport's standards but is refusing even that chance to the Concorde. Indeed, the Justice Department says the noise standards that stand in the way of the Concorde are violated "regularly" by subsonic airplanes but that these violations are ignored by the Port Authority.

This brief merely confirms our view that the Port Authority has acted unreasonably and unwisely in this protracted struggle. By any standard of basic fairness, the Concorde is entitled at least to the trial period that has been authorized by the Secretaries of Transportation of both the Ford and Carter administrations. And by aby standard of decent respect for the problems of international cooperation, the Port Authority should stop prolonging this matter and treating the planes' owners in such a high-handed manner. If the courts concur with the Department of Justice's assertion of discrimination, the trial period ought to get under way as quickly as possible. If they do not concur, it may become necessary for Congress to give the Department of Transportation the authority to override local governments on matters concerning international aviation.