Transportation Secretary Federico Pena has apparently decided to make open skies his personal Holy Grail, and to his credit, in two years he's accomplished more to liberalize air commerce than any of his predecessors in recent memory.

For starters, last fall Mr. Pena unveiled a new international aviation policy that revealed a far more clear-eyed view of the global scene than has been seen before at the Transportation Department. For example, the DOT finally bowed to the inevitable and reversed its position on code-sharing between U.S. and foreign carriers, acknowledging that such partnerships are on the increase, and probably for the better.It's not startling news to hear that another federal agency has added another sheaf of documents to its groaning shelves. But the DOT actually seems to be using the new policy to guide its aviation activities.

Since the policy was issued, changes in the United States' bilateral accords with other countries are proceeding at a dizzying pace, by international negotiating standards. And Mr. Pena is proving to be a tough, tenacious and pragmatic negotiator as he closes his deals.

He proved conclusively that he's not afraid to go to the wall in the recent aviation war against Japan.

Federal Express Corp. is doing belated cartwheels in Memphis, now that Tokyo has assured the carrier it can serve seven new routes from Tokyo and Osaka's Kansai Airport from its Asian cargo hub at Subic Bay, Philippines. FedEx is opening Subic Bay on Sept. 4, two months later than scheduled. But better late then never.

Until July 21, Tokyo absolutely refused to honor what the U.S. government said were the terms of its aviation pact with us, which dates back to 1952, and let FedEx fly those routes. Mr. Pena announced in June that the DOT was ready to impose sanctions against Japanese air cargo carriers if Tokyo wouldn't cooperate. The DOT issued a so-called show-cause order to Japan Air Lines and Nippon Cargo Airlines, under which they were required to justify why the U.S. government should allow them to continue their scheduled cargo services while FedEx is denied its rights under the accord.

Japan finally caved in, but there's undoubtedly more to this story than meets the eye. In return for the FedEx routes, the United States agreed to renegotiate cargo rights with Tokyo - but U.S. officials had said all along they would be pleased to do that, if Japan would let FedEx fly. In his negotiations, Mr. Pena apparently managed to gloss over the real prize, passenger rights. Now the aviation community is waiting for the other shoe to drop.

Unfortunately, Mr. Pena hasn't been having much luck with China. Talks with that country are stalled, although at least the United States hasn't been talking sanctions. The Chinese want the United States to defer implementing seven additional flight frequencies that were scheduled to take effect earlier this spring under the terms of the bilateral, saying the agreement is unbalanced in favor of U.S. airlines.

Fights with the Far East aside, Mr. Pena's coup to date is unquestionably Canada, with which the United States signed a long-awaited liberalized bilateral air agreement during President Clinton's trip to Ottawa in February. In all fairness, the United States had been trying to modify the previous agreement - which was so severe that airline cargo and passenger travel was virtually stagnant between the two countries - for more than 15 years. But the Canada accord was finally signed under Mr. Pena's watch, so he gets to claim the victory.

The agreement removes most restrictions on all air cargo service immediately, and virtually deregulates the industry within 12 months. Mr. Pena said liberalizing the Canada accord will spur more than $1 billion in new economic activity.

Another bright spot was the June deal between the United States and Brazil to expand air services between the two countries. Brazil is the United States' largest South American market, with 1.6 million passengers traveling between the two countries in 1994. Both passenger and cargo traffic between the United States and Brazil increased by more than 20 percent between 1993 and 1994.

A little-touted but significant step is the eight new open skies pacts the United States signed with small Western European countries in June. The Clinton administration has closed deals with European Union members Austria, Belgium, Denmark, Finland, Luxembourg and Sweden, as well as Norway, Switzerland, and Iceland. As of this writing, only EU member Belgium had not signed the pact it had already negotiated with the United States.

EU Transport Minister Neil Kinnock, who decided in March to contest the right of the six EU countries to negotiate individually with the United States on the pacts, continues to scream bloody murder over the arrangement, but too bad - it's now a fait accompli. Passengers and cargo shippers probably won't reap benefits this summer, but the fall could bring some real bargains for cost-conscious consumers with Europe on their minds.

There's strength in numbers, and open skies agreements with this block of nine small Western European countries could act as a flying wedge to persuade France, Britain, and Germany to loosen up.

Speaking of Britain, the jury is still out on Mr. Pena's decision to strike a series of "mini-deals" with London to modify the current bilateral. That deal angered many powerful members of Congress, whose judgment certainly is not colored by the geographical locations of certain major airlines that don't want to see more slots at Heathrow International Airport go up for grabs.

There are three plenary sessions scheduled this summer to negotiate the terms of a wider deal with Britain that may ultimately do just that - open additional access to Heathrow for U.S. carriers.