For all the brouhaha over the bonanza at Boeing-and fears that the aerospace giant would fly away with the commercial airplane market-an interesting fact fell out from last year's industry figures: Boeing actually lost market share.

That bit of news was drowned out in all the fanfare over record others for 747s, over the unveiling of a new line of economy jets, over a total sales figure that topped $11 billion and, more recently, over the disclosure that Boeing's chairman and its president each earned more than $1 million last year in salaries and bonuses.

In the final accounting for 1978, though, Boeing's share of world orders for commercial aircraft slipped 2 percent from 59 percent to 57 percent. Lockheed fell, too, from 7 percent to 6, and McDonnell-Douglas gave up the most, sliding from 28 percent to 17.

Who was picking up the pieces? Clearly the Europeans, who through a consortium called Airbus Industrie, ran their share up from 6 percent to 19 percent in a single year.

Backed by the French, West Germans and Spanish, Airbus was chartered to carve out a chunk of the commercial airplane market long dominated by the Americans. Last year it sold 132 of its key products-the A300, a medium size, medium range aircraft. It also introduced the A310, a smaller version designed to compete directly against Boeing's much touted 767.

Earlier this month two major European airlines rejected the 767 and placed large orders for the A310. The orders totaled $1.3 billion with West Germany's Lufthansa buying 25 aircraft and KLM Royal Dutch Airlines buying 10. Another 10 have been bought by SwissAir.

Boeing officials profess not to be more worried than usual about their European competition. They claim to have all the business they can handle at the moment. If Boeing's market share declined last year, it was, they say, because the market itself grew explosively, from 357 planes worth $6.9 billion in 1977 to 730 planes worth $17.6 billion sold in 1978.

Boeing executives call "silly" and "dumb" a press report two weeks ago that the company is "rethinking" the 767 in view of Airbus' recent success.

"We've had no surprises," said Clarence Wilde, Boeing vice president for marketing and sales, adding that the company had expected tough competition from the Europeans. "There has been nothing so far that has caused us to change our strategy," he said.

But the competition for new planes to replace the airlines' aging fleets is in its early phase with a long race still ahead.

Boeing, of course, expects to emerge a winner. It anticipates selling 750 of the new planes by 1990 in a market it projects will buy 1,500 in all.

Many of those sales, however, are likely to come simply from this side of the Atlantic while Airbus pushes on in Europe. So far Boeing has had orders for 80 737s from three domestic airlines-United, American and Delta-but only one foreign order, a four-aircraft sale to a relatively small Canadian carrier, Pacific Western Airlines.

Wilde predicted Boeing would sign up another five customers for the 767 by the end of this year, for anywhere from 30 to 50 planes. Probably none, he said, would go to a European airline.

Overseas sales have been an important part of Boeing's total business, amounting to 53 percent of the company's orders last year. For the U.S., too, foreign plane sales count heavily-commercial aircraft is the nation's No. 1 net export.

But Boeing officials warned these sales are now threatened by the rise of Airbus. And they say the contest may be tilting in favor of the Europeans because their governments are more sympathetic to Airbus' needs-and are willing to deal.

Though the terms of Airbus contracts have not been disclosed, it has been widely reumored that some have hinged on important concessions by European governments to foreign powers, including the granting of landing rights at European airports, arms sales tie-ins and extraordinary financing terms.

Meantime, the U.S. government and its foreign trading bank, the Export-Import Bank, have not been willing to go as far to clinch a sale. Boeing is hoping for more government support in the future.

"We've been trying to impress upon the Ex-Im Bank that Airbus competition is real," Wilde said.

In response, Ex-Im Bank officials say they already have been generous to Boeing and flexible in their financing of foreign aircraft orders. The bank's budget is up, and it has been loaning money below the prime interest rate.

At the same time, Griff Ellison, a bank official, said he expected the bank to be "even more aggressive in the future," though he doubted the U.S. would choose to match some of the political tie-ins reportedly offered by the Europeans in return for aircraft sales.

Boeing's frustrations stem not only from less-than-desired home support. To build the 767, Boeing subcontracted part of the plane to the Italians, hoping to tap some European sales that way. But to the company's dismay, Italy's main airline last year ordered four jets-from Airbus.

One other factor that has crimped Boeing's foreign sales effort has been Washington's fuss over so-called "questionable payments" abroad. Boeing has disclosed it paid "foreign consultants" $53 million during a recent seven-year period in connection with plane sales.

All the publicity over foreign bribes by U.S. firms has had an effect on Boeing. "It has helped Airbus," Wilde remarked.

The battle for dominance of the world commercial airplane market is likely to be determined neither in the U.S. nor in Europe but along the Pacific rim, Asian subcontinent and Arabian Gulf-the historic "silk route" demand for aircraft is increasing rapidly there, and Airbus is working effectively, having already made large sales to Pakistan, the Philippines and Greece.

Boeing could find itself at a competitive disadvantage when European carriers that have already bought Airbus planes start using them on runs to the Mideast and North Africa. Those countries have been good customers for Boeing in the past, but carriers in those regions may feel the need to match equipment with some of their European competitors.

For now, Boeing is flying high, trailing a long back-order list for the mammoth 747 and the shorthaul 727 and 737. The company also has received sizable orders from Eastern Airlines and British Airways for the 757, a new short a medium range craft.

"It's wrong to think we're in a reactive mode," said Kenneth Holtby, Boeing vice president for new programs. Short of a world-wide depression, Holtby said Boeing has no plans to change its current course. CAPTION: Picture, A mock-up of the highly touted, wide-bodied Boeing 767, shown at the firm's plant in Renton, Wash.