As if he didn't already tower over his fellow lawmakers 6 foot, 11 inch Rep. Tom McMillen (D-Md.) yesterday floated high above Andrews Air Force Base in a helium-inflated blimp that is being billed by some as the latest innovation in aerial defense.

"It's pretty wild, isn't it?," proclaimed the freshman lawmaker, surely Congress' biggest blimp backer, as he crouched inside the dirigible and touted its potential benefits, military and economic, to a small group of somewhat queasy reporters and photographers.

The McMillen voyage was the latest sign that blimps may soon be back, courtesy of the Pentagon. Last month, the Navy awarded a $168.9 million contract for the construction of a new giant blimp prototype that would dwarf the famous Goodyear blimp and could eventually be used for aerial surveillance purposes. The idea is that massive 423-foot long, radar equipped airships would hover 10,000 feet above aircraft carriers and other surface vessels and warn them about incoming dangers, such as Exocet missiles.

McMillen's interest is not purely strategic, though. After a hard-fought competition, a joint venture company formed by Westinghouse Electric Co. and the British-based Airship Industries was selected to build the model, beating out Loral Corp., which earlier this year acquired Goodyear Tire & Rubber Co.'s aerospace operations, long the leaders in blimp operations.

Although construction will be in Elizabeth City, N.C., the Westinghouse-Airship management team will be housed in offices at Hanover, Md., adjacent to Baltimore-Washington International Airport and squarely inside McMillen's 4th Congressional District. Assuming the Navy exercises its option to build five more prototypes, the program would bring about 200 mostly high-paying new management jobs to the Hanover facility, according to officials at Westinghouse, which is already the largest private employer in Maryland.

But McMillen and Westinghouse officials clearly have bigger things in mind. The Navy has talked about purchasing a fleet of up to 50 blimps. Some analysts envision that the blimps will be deployed for intercontinental defense, patrolling the eastern seaboard for incoming cruise missiles. Westinghouse also sees the U.S. Customs Service as a potential customer, using the airships for drug interdiction in the Caribbean.

"This could be billions, depending on how much the Navy chooses to buy," said Jerry Coppel, marketing director for Westinghouse Defense and Electronic Systems Co.

While critics have suggested the big blimps will be tempting targets in their own right, Coppel says that new innovations in blimp technology -- stronger hulls, more maneuverable engines -- have fueled the airship revival. Blimp backers also argue that recent events have strengthened their case: The May 17 attack on the frigate Stark has underscored the vulnerability of surface ships, a concern that was previously highlighted during the 1982 Falklands War, when a single Exocet sunk the British frigate Sheffield.

"It's a technology whose time has come again -- and the fact that they are so economic fits the times," said Coppel.

Yesterday's voyage from Andrews was designed to drive home the point. Proud of its new contract, Westinghouse teamed up with McMillen's staff to sponsor a "test flight" for the press on a mini-dirigible, which Airship now uses for tourist rides in London, San Francisco and Sydney. The Navy's blimp will be 423-feet long and 150 feet high with a double-deck gondola, complete with TV room, weight-lifting room and what a press release calls "semiprivate staterooms" for the 10-man crew.

Yesterday's test dirigible was less than half the length, 193 feet, about one-tenth the volume and had cramped quarters that barred McMillen from standing up.

It also raised some questions about the true state of blimp technology. During takeoff, a support team of hefty crewmen wearing red T-shirts and shorts were needed to hold down two tether ropes to prevent the blimp from being swept away by the winds. The same team rushed out during landing to grab the ropes and ease the airship down.

Asked if he considered such methods cutting-edge technology, McMillen laughed and moved on to the airship's other advantages.

"For me, this is good," he said. "It's good to be able to do something for the largest employer in your district."