There is probably no other company that so thoroughly dominates a global industry as the Boeing Co. dominates the multi-billion-dollar market for commercial jet aircraft.

There is Boeing, and then there is everybody else.

Since 1958, the Seattle-based company has delivered over 3,500 of its 707s, 727s, 737s, and 747s to 177 customers, accounting for over 50 percent of worldwide commercial airplane sales.

But rather than decreasing, that dominance has been growing - by leaps and bounds - as airlines, benefitting from surging passenger traffic, line up to purchase a new generation of quieter and more fuel-economical planes that they hope will see them through the 1980s.

Today analysts estimate that Boeing accounts for 70 percent of the dollar sales of jet aircraft to U.S. airlines, and between 60 and 65 percent of sales worldwide.

Yesterday's announcement that Eastern Airlines and British Airways have placed orders for a total of 40 of the new Boeing 757 - a narrow-body jet seating 150 to 180 passengers - at a cost of $1.3 billion is only the latest example.

This is the second new aircraft program Boeing is embarking on this year.

In July, United Airlines placed the initial order for the Boeing 767, a wide-body, short-range jet capable of carrying up to 300 passengers. The order for 30 of the new planes at $1.2 billion represented the biggest single order in aviation history. It was capped by an additional order from United for 30 Boeing 727-200s at a cost of $4 00 million.

And within the next few months Boeing is expected to announce yet a third new aircraft program, the 777, which is a three-engine version of the 767, providing the airplane with an intercontinental range of 4,500 to 6,000 miles.

The announcement will depend on a probably order from American Airlines, which is expected to buy between 20 and 30 of the new planes, at a price-tag of $35 million to $40 million each.

No other aircraft company in the jet era has had the boldness to launch two new airplanes at the same time, let alone three, and Boeing must lay out a staggering $4 billion in startup and development costs over the next few years to carry it out.

But aerospace analysts believe that Boeing has the financial wherewithal and customer base to pull off what is in effect a preemptive strike that is leaving McDonnell-Douglas, Lockheed and the European airbus-industries - its major competitors - standings on the runway.

Adding to the company's strength is the fact that its current airplanes continue to sell well. Singapore Airlines in May placed $900 million in orders for 13 747s, the original "jumbo" jet, and six medium-range 727s.

"There's no way they can be dislodged," said Alan Benasuli, aerospace analyst with Drexel Burnham Lambert.

"The key to their success is very simply," he added. "They have a complete product line, which nobody else has. And they already have planes with 90 percent of the airlines in the world, so they have an enviable customer base. And if an airline reorders, other things being equal, they are going to reorder Boeing."

Financially, Boeing is in good shape to tackle its ambitious three-pronged program. It currently has about $1.3 billion in cash and more than $1 billion in share holders equity. Sales for 1978 are expected to approach $6 billion and the order backlog at midyear was $6.9 billion.

In the first six months of 1978, Boeing posted a 45 percent increase in earning to $122.7 million or $2.88 a share. Benasuli projects earnings for all of 1978 at $7.25 a share, up from $4.24 a share or $180.3 million in 1977.

The Drexel Burham analyst projects earnings to continue to increase in the next few years, reaching between $10 and $11 a share in 1980. Then he sees a temporary drop between 1961 and 1963 as "research and development and general and administrative expenses go up dramatically at the same time that their revenues from current planes will be coming down."

A number of airlines are expected to hold off purchases of Boeing's present lines of airplanes as they wait for the next generation of jetliners to become available, beginning in 1962.

But for now Boeing is having to accelerate its current production of airplanes from 18 a month to 27 a month by the end of 1979 just to fill its order backlog.