Cancellation of the B-1 bomber program dashed hopes yesterday in corporate boardrooms from Long Island to Los Angeles, and threatened to put thousands of people, who had been designing everything from wings to wheels for the supersonic transport, out of work.

But many of the companies which had been planning on a share of the $100 billion-plus program including Rockwell International, which as main contractor has the most invested in the plane - said termination would have little effect on earnings this year.

The big loss for Rockwell and dozens of other contractors will be in terms of what might have been. "The company will lose the long-term potential production would have offered us," a Rockwell spokesman said.

Trading in Rockwell stock was suspended for four hours yesterday after President Carter's announcement. The stock price had risen slightly early in the day, refelcting speculation in the morning papers the project would be approved.

When trading resumed, the price had dropped $4.75 to $32, but that was the low for the day. The stock closed at 32 3/8. Market analysts predicted the stock had slipped as much as it would in response to the B-1 decision, and predicted termination of the project may even prove to be a positive factor for Rockwell in the long run.

"It's certainly not a disaster for Rockwell," said John Simon, an aeronauties industry financial expert with the Los Angeles-based brokerage firm Crowell, Wheedon & Co. "Maybe now the company management will stop all the politicking and put some of its top people back to work building up other divisions, such as Admiral."

Rockwell had 16,000 persons working on the B-1 project, including designers and engineers at a plant in El Segundo, Calif., machinists at an assembly plant in Palmdale, and avionics experts at Edwards Air Force Base where three prototype aircraft built by the company have been undergoing tests. Since 1970, when Rockwell won the B-1 contract, more than $2.8 billion has been spent on the program.

A spokesman for the company said 10,000 persons will have to be laid off as a result of the cancellation, about 8,000 of whom are in the Los Angeles area. The entire corporation has about 115,000 employees.

Nationwide, more than 30,000 will be directly affected by Carter's decision, facing either transfers to other projects or layoff slips. A spokesman for the General Electric Co., developer of the engine for the B-1 bomber, said employment at all aircraft engine facilities will be affected to some degree, with the principal impact coming at the Evendale, Ohio, plant near Cincinnati.

Because full-scale production had not begun, the immediate effect will be small. "However, employment in the early 1980s, when peak engine production was planned, could be severely affected unless other engine programs are acquired to replace this cancellation," the GE spokesman said.

The Boeing Co., an associate contractor responsible for developing the B-1's offensive aviation electronic equipment (navigation and radar systems, weapons, etc.), had 400 employees working on the project, all of whom, according to a spokesman, will be transferred to commercial projects such as 727 and 747 airplane production and to the cruise missile project.

Other firms affected by Carter's decision to scrap are:

Cutler-Hammer, which would make the plane's defensive systems; Good-year Tire and Rubber, which would have provided the wheels; Goodrich, which would have produced the tires; Bendix Corp. which would have manufactured the controls; Sperry-Rand Corp., which was developing the flight control computer and display terminals.

Also, LTV, which would have supplied the aft fuselage; Sundstrand Corp., which would have provided the constant speed drive systems; United Technologies, which would have manfactured the air conditioning and pressurization systems; Menasco Corp., which would have made the nose landing gear: Cleveland Pneumatic Tool Co., which would have made the main landing gears; Texas Instruments, which would have provided the radar system that would have enabled the plane to fly at extremely low altitudes: Avco Corp., which would have made wing parts; Collins Radio, a subsidiary of Rockwell International, which would have built the tape recorders and radios for the aircraft.