The financial problems besetting some of the world's biggest airlines have begun to affect the aircraft manufacturing industry, one of America's largest export earners whose continued overseas sales are seen as crucial for pulling the United States out of the recession.

From Australia to Great Britain, airlines are pulling back on orders as fuel costs have risen and their business has plummeted because of economic hard times and the increased fear of terrorism.

The impact has been felt by Airbus Industrie, the European consortium, as well as the two leading American manufacturers, Boeing Co. and McDonnell Douglas Corp. The major makers of aircraft engines, Great Britain's Rolls-Royce PLC as well as General Electric Co. and Pratt & Whitney Group of the United States, are also expected to feel the impact of the massive downturn in airline business.

The effect on manufacturers came through most sharply yesterday when both British Airways Ltd. and Australia's Quantas Airways announced cutbacks in airplane orders.

British Airways PLC said that the sharpest downturn in passenger service in its history forced it to postpone a $2 billion aircraft replacement program and to defer putting into service five Boeing 767 planes it will get this year. Quantas said it was stretching out the delivery schedule of $1.9 billion in new Boeing jets that it was scheduled to receive this year and next.

The news quickly reverberated on Wall Street, sending Boeing Co. stock tumbling $3.12 1/2 to $48.25 and making it the most actively traded stock. "It's not a commentary on Boeing as a company, which will continue to do well. It's a commentary on Boeing the stock. The reality will be well below the investment community's expectations of a lot of strong orders," said Michael Rosen, an aircraft industry analyst with the brokerage firm of Smith Barney, Harris Upham & Co. in New York.

He said that "deteriorating traffic" and a cutback of 10 percent to 20 percent in capacity means that airlines will be forced to reduce orders for new planes. Over time, this will result in delays of deliveries, options to buy new planes not being exercised and a stretching out or outright cancellation of deliveries, Rosen said, as he downgraded Boeing stock from a "hold" rating to one to be avoided.

Any cutback in aircraft orders could hurt the Bush administration strategy of using exports to pull the United States out of the current recession. Overseas sales was the strongest segment of the U.S. economy last year, responsible for as much as 80 percent of economic growth, said Jerry Jasinowski, president of the National Association of Manufacturers.

The two major American makers of commercial jets, led by Boeing, accounted for 5 percent of all U.S. exports last year and showed the U.S. domination of the commercial aviation market by running a $15 billion trade surplus for the first 11 months of 1990.

A senior administration official noted that there were wide swings in the overall U.S. trade balance during months in which Boeing or McDonnell Douglas failed to export planes.

A Boeing 747 costs as much as $200 million while the smaller 767s are valued at about $130 million each.

The problems go beyond the United States. Jean Pierson, manager of the European Airbus consortium, said he expects orders to fall by one-half this year after a banner 1990, when there were 440 orders for Airbus planes. Many of the orders came from Middle East airlines, which have been especially hard hit by the Persian Gulf War.

Airbus spokesman David Venz said that Air France has pushed back delivery of seven Airbuses for a year, which Venz said was "the more logical way to go" because it avoids canceling an order. A Middle East carrier canceled its order for one plane.

Boeing spokesman T. Craig Martin, whose company has a backlog of 1,800 orders with delivery dates stretching to 1999, said some airlines are discussing the possibility of postponing deliveries to avoid having to pay for planes when business is so slow. "We are talking to some folks about how we could help them," Martin said.

Don Henson of McDonnell Douglas said only one carrier has canceled an order. He added that orders remain strong for its new plane, the MD-11, on which the company is basing its future in the commercial aviation business.

.............CIVILIAN..........TRANSPORT..........TOTAL, AS A

.........AIRCRAFT (IN.......AIRCRAFT (IN........PERCENTAGE OF

......... BILLIONS OF........BILLIONS OF..........MERCHANDISE

............ DOLLARS).......... DOLLARS)..............EXPORTS

1980..........$13,248.............$6,727.................6.9%

1981...........13,312..............7,180.................7.4

1982............9,608..............3,834.................7.2

1983...........10,595..............4,683.................7.8

1984............9,659..............3,195.................6.7

1985...........12,492..............5,518.................8.6

1986...........14,851..............6,276.................8.7

1987...........15,768..............6,377.................8.8

1988...........20,298..............8,766.................8.4

1989...........25,619.............12,313.................8.8

1990........................................................

1st quarter....$7,910.............$4,243..................NA

2nd quarter.....8,414..............4,696..................NA

3rd quarter.....7,638..............3,927..................NA

NOTE: Transport aircraft, which are included in the civilian total, include passenger airliners and cargo planes. Total aerospace exports include military sales.

SOURCES: Census Bureau's Foreign Trade Division; Aerospace Industries Association, based on data from the International Trade Administration.