LONG BEFORE MOST Americans would speak of macho and Mach numbers to describe the virility and skills of that great national hero-- The U.S. Military Pilot--there were crack Navy and Air Force stunt teams dazzling tens of thousands of gasping onlookers with death-defying aerobatics. Then as now, the Blue Angels and the Thunderbirds would swoop, dive, roll and loop in tight precision patterns that had to impress even the roughest critics of the military. But over the years since the birth of the Blue Angels in 1946, death has not always been defied--and on Monday, the worst disaster in the history of this military air stunting left four Air Force Thunderbirds dead in a four-plane crash 40 miles north of Las Vegas.

And on cue, now as then, each time there is death there are calls for an end to all this tax-supported daredevilry--and forget any glamor, national pride or international prestige that military officials do attach to these performances. Is there any reason for taxpayers to continue sponsoring this dangerous show business--or, as Pentagon officials have suggested before, are critics simply seizing on rare instances of tragedy to tear down a popular tradition that attracts recruits, boosts military morale and points up the excellent skills of today's pilots?

The cost--in lives as well as dollars--cannot be dismissed lightly: since 1946, the Navy has lost 19 men in aerial acrobatics, and the Air Force, which first sent up the Thunderbirds in 1953, has lost 19 men and 29 planes. In all, the losses of aircraft are estimated to be more than $50 million. Regular operating costs are slight in budget terms; Air Force officials estimate that the Thunderbirds cost about $6.3 million a year for fuel, salaries and other expenses.

Even stipulating that the dollars are not enough to justify eliminating these performances, there is strong reason to consider the changed nature of these shows--with jets that scream through the air toward each other at hundreds of miles an hour and then fly wingtip to wingtip at 400 miles an hour 100 feet above ground. Why must these extremely close-tolerance maneuvers at near ground level--which often cannot even be seen by most of the thrill-seeking spectators--be carried on?

If the Pentagon insists on staging these stunts-- including aerobatics of highly questionable wartime significance--the repertoire should be revamped to eliminate the pointless, high-risk maneuvers most likely to endanger pilots and spectators. In 1973, after a series of fatal crashes canceled performances by the Blue Angels, such revisions were made--not only in the types of planes used but in the number of maneuvers and distance between aircraft. As former Navy secretary John W. Warner (now a Republican senator from Virginia) said about one upside-down, low- level maneuver that ended in the death of a pilot, "Damn it, there is just no requirement for that. It's unreal and in my judgment encroaches on the safety of the fliers and the spectators."