Nicaragua has sent out urgent appeals "everywhere" for combat aircraft to bolster its defenses against attacks by CIA-backed rebels, but "the United States has put ample pressure" on its Western allies to turn down the requests, according to Sandinista leader Daniel Ortega.

Leaving open the possibility of turning to the Soviet Union to build the Air Force considered necessary to counter rebel air attacks and potential conflict with neighboring Honduras, Ortega said in an interview that he saw "no reason why the brand name of the planes should worry the United States."

The Sandinistas have received substantial quantities of arms from the Soviet Union, and Soviet-made weapons from other countries. But they have virtually no Air Force. The Honduran Air Force is the best-equipped in Central America.

While Nicaragua gets economic aid from Western Europe, its only substantial arms transaction with the West involved a $15.8 million purchase of helicopters and other equipment last year from France.

The Socialist government of French President Francois Mitterrand is known to disapprove of U.S. policy in Central America. But it has tempered its public criticism because of low-level disagreements with the Reagan administration in other areas that are considered more immediately vital, and because it has concluded that Central America remains within the "U.S. sphere of influence," according to French officials interviewed over the past year.

Although Paris has remained on friendly terms with the Sandinistas, and 10 days ago received Nicaraguan Interior Minister Tomas Borge, the Mitterrand government has let it be known that it will not entertain further requests for arms sales to Nicaragua.

Questioned on U.S. warnings about the Nicaraguan acquisition of Soviet planes following reports that Sandinista pilots had trained in Bulgaria on Soviet MiG23s, Ortega said, "There have been so many threats from the United States, we lose track of them."

Ortega, speaking in an interview Monday night in New York, said that instead of Nicaraguan defense procurement, "what ought to concern the United States is that it was incapable of giving an adequate response to the political and social problems" of Central America in the past, and is now reaping the results. "The Nicaraguan revolution is the fruit of bad U.S. policy," including decades of support for the Somoza family's dictatorship overthrown by the leftist Sandinistas in 1979, he said.

One of the nine members of the ruling Sandinista National Liberation Front, Ortega also serves as "coordinator" of the three-man government junta and is effectively head of state. He arrived in New York Sunday for an address yesterday to the U.N. General Assembly.

Ortega said he hoped his interview with The Washington Post and other contacts will help influence U.S. public and congressional opinion. Acknowledging that outsiders' interest in Nicaragua and opposition to U.S. policy there appeared to have waned in recent weeks, he said an "appeal to international public opinion and U.S. domestic opinion" was one of the few ways left to avoid a direct confrontation between Nicaragua and the United States.

Nicaragua's current policy, Ortega said, is "to continue promoting dialogue, a political solution to the problems" of Central America. But the U.S. answer so far to Nicaraguan peace overtures, he said, has been "warships . . . North American soldiers to surround us, and now, planes to bomb us."

Although the Sandinistas publicly have offered to discuss all issues between them and the United States--including their support for guerrillas fighting the U.S-backed government in El Salvador and the presence of what the administration says are as many as 2,000 Cuban military advisers in Nicaragua--progress toward substantive dialogue has been scant. As a result, Ortega said, Nicaragua also is "going to have to fortify our efforts in defense, and prepare ourselves to confront an eventual North American intervention."

Last week, administration officials reportedly told Congress their goal in Nicaragua was no longer merely to stop alleged arms shipments to El Salvador but to induce the Sandinistas to stop their alleged support of subversion in other countries.

In his U.N. speech, Ortega said that in "January 1981, the new U.S. administration declared war on the people of Nicaragua." Enumerating alleged U.S. offenses, he listed "203 spy flights and 512 violations of Nicaraguan airspace" and 34 violations of territorial waters. He said 717 Nicaraguans had been killed in attacks by U.S.-backed rebel forces since 1981, while the Sandinistas have "annihilated 1,636" rebels. Economic damage from "U.S. aggression," Ortega said, has totaled "$108.5 million . . . amounting to one-quarter of our annual investments."

Over the past several weeks, anti-Sandinista rebel forces headquartered in Honduras, to the north, and in Costa Rica, to Nicaragua's south, have stepped up ground attacks against rural outposts and urban centers inside Nicaragua and have begun using light aircraft for bombing raids on strategic economic targets.

The largest of the groups, the CIA-backed Nicaraguan Democratic Force, last week launched what the Sandinistas describe as its third major offensive this year in the northern part of the country. In communiques, the Honduran-based group has announced a new stage of "urban guerrilla warfare."

Reporters visiting those regions this week found that the rebels appeared to have been driven back by Sandinista forces. But the newly intensified rebel activities, the apparent coordination between distinct rebel groups in the north and south, the air attacks and what Ortega said was increased participation by the Honduran Army in support of the Nicaraguan Democratic Force clearly have heightened Nicaraguan concern.

Ortega said in the interview that the rebels moved into position for attack last week with substantial assistance from the Hondurans, including transport of the rebels to the border and cover with "mortars, cannons and even tanks." Honduras repeatedly has denied similar charges.

Although he described the rebel attacks as "desperate actions . . . the product of the stinging military defeats they have suffered," Ortega said that the Sandinistas had stepped up their weapons procurement program.

Asked where the Sandinistas were looking, Ortega said, "Everywhere."