A bright spot in Ulster economy is two-year output of US private jets

Despite the De Lorean auto debacle and 19.5 percent unemployment, the Ulster outlook is not entirely gloomy. This is demonstrated by the success in Northern Ireland of the Lear Avia Corporation of Reno, Nev.

Two years ago the British government announced an agreement with the US company to develop the Lear Fan 2100 in Northern Ireland and in Reno. The plane is a nine-seater executive craft with a revolutionary design.

Lear Avia was established by Mrs. Moya Lear, the widow of the Bill Lear. Lear was an aviation innovator who launched the Learjet range of aircraft and later sold out to the Gates Rubber Company, which now produces the Gates Learjet. Bill Lear planned a new concept, the Lear Fan 2100 aircraft, made with carbon fiber and reinforced plastic to reduce weight and give it a superior performance. The design also specifies two gas turbine engines driving a rear ''pusher'' propellor.

The funding for the initial development has come from four sources: from Lear Avia itself; from nonreturnable deposits on advance orders; from money raised by a US investment specialist, Oppenheimer & Co.; and a $30 million loan guarantee from the British government.

The aim was to provide employment for 1,250 people in Ulster within five years and to produce 200 aircraft a year. Giles Shaw, the government minister in charge of industry in Northern Ireland, said at the time, ''The Lear Fan 1200 represents a first in aviation technology, not only in the United Kingdom, but possibly in the whole of Europe.''

Since those hopes were expressed in February 1980, there has been good progress. Already 560 people are employed at the Lear Fan factory in Carnmoney, six miles north of Belfast, and there are 263 advance orders for the aircraft. The company expects this to rise to 300 in the near future. The target of 200 aircraft a year may be exceeded by another 60 annually, provided advance orders maintain the same encouraging rate.

Mrs. Lear said recently that the work force in Ulster should rise to 1,000 by the end of this year. It is believed that given favorable conditions the company may exceed the original employment estimate of 1,250.

It is currently in the process of raising a further $30 million from US and British investors to help with development costs.

In a lunch address to businessmen and professionals, Mrs. Lear expressed her confidence in the Ulster employees. ''We have the most wonderful relationships in Northern Ireland and we are really proud of the work force,'' she said.

The company intends to build the first 42 aircraft in Reno, partly with components made in Ulster. The rest will be made and assembled in Belfast, and Reno will concentrate on research and project development.

Meanwhile, efforts are continuing to consolidate the jobs of the remaining 1, 500 De Lorean workers in Belfast and to find a buyer for the Belfast-based company, which is now in receivership. Sir Kenneth Cork, the receiver, confirmed in Belfast that attempts were being made to sell 500 De Lorean cars - possibly 1 ,000 - to Budget Rent-a-Car, one of the major US rental companies. Sir Kenneth said anyone who supplied materials to the company from now on would be paid cash.

A number of small manufacturing companies that are creditors of the company have written Sir Kenneth seeking guidance. An estimated 5,000 jobs among suppliers throughout Britain depend on De Lorean's survival.

But investment from industries is not enough to put the needed life in the province's economy, resident economists say. In a disheartening report on the province's future, economists Desmond Rea and Stephen Harvey from the Ulster Polytechnic have called for radical government action in setting up state enterprises to provide work. They warn that the two main government strategies (to encourage small firms and to attract overseas investors) will not create enough new jobs to reduce significantly the unemployment lines.