It was billed as a congressional hearing on proposed budget cuts to the National Endowment for the Arts, but those who showed up heard almost as much Pentagon-bashing as art talk from performers angry about Reagan administration proposals to increase defense spending and let federal arts support decline.

New York choreographer and ballet director Eliot Feld went so far as to suggest formation of a "National Endowment for Defense . . . 'NED' to its friends," that would require the Defense Department to submit grant proposals for military programs in much the same way that individual artists and arts organizations now apply to the National Endowment for the Arts for federal money.

"The Defense Department would . . . submit grant applications, running the gamut of their needs from laser beams to K-rations, and the NED would approve those applications that merited NED support in the amount of 50 percent of their cost," Feld told a House appropriations panel chaired by Rep. Sidney R. Yates (D-Ill.)

"The beauty of this plan," Feld deadpanned to an impassive Yates, "is that it . . . potentially provides full funding for the Defense Department." After two years under this system, Feld said, "the Defense Department will have had sufficient opportunity to develop its own survival skills and should be able to compete for funding on the same terms as theater companies, orchestras, opera companies, museums and ballet companies."

Although the proposal was tongue-in-cheek, Feld's plea for arts funding was echoed by other witnesses including Pulitzer Prize-winning playwright Marsha Norman, pollster Louis Harris and James DePreist, music director of the Oregon Symphony Orchestra.

"Where is our sense of proportion, our sense of balance?" Feld asked Yates and Rep. Ralph Regula (R-Ohio), the only two congressmen in attendance for much of the morning. "Have we not reached the point where every additional dollar we spend on defense diminishes the quality of life it was designed to protect?"

The Reagan administration has proposed cutting the budget of the National Endowment for the Arts by 11.7 percent next year, from its current $163.7 million to $144.5 million. Representatives of the trade associations that represent arts organizations are requesting a budget of $175 million, a 7.3 percent increase.

Reagan also has proposed to boost military spending in 1986 from $284.7 billion to $313.7 billion, an after-inflation increase of 5.9 percent.

The administration sent its proposed budget to Congress in February. Yesterday's hearing was the beginning of a season of hearings before the House and Senate appropriations subcommittees that establish the endowments' budgets.

In past years, Congress has ignored Reagan administration proposals to slash those budgets and instead raised them each year. This year, however, Yates, as well as Sen. Claiborne Pell (D-R.I.), both longtime supporters of the arts, have suggested that concern over the federal budget deficit may block the traditional increase.