Banner Industries, which is based in Cleveland, has a controlling interest in Fairchild.

Surrendering after a five-month struggle to remain independent, Fairchild Industries agreed today to be acquired by Banner Industries for $18 a share in cash, or a total of about $265 million.

Banner Industries, a metals firm, acquired Fairchild Industries in August 1989.

LEAD: Banner Industries appointed Emanuel J. Fthenakis as president and chief operating officer.

LEAD: * Avdel P.L.C., a British assembly-systems company, urged its shareholders to reject a $102 million takeover offer from Banner Industries, Cleveland.

Jeffrey Steiner, chairman and chief executive of Banner Industries, a diversified manufacturer in Cleveland, has taken the final steps to acquire Rexnord Inc. for about $525 million.

The company last month rejected an $84-a-share offer from Banner Industries.

It was bought by Matra from Banner Industries for $245 million last August.

In 1989, Fairchild Industries was purchased by Banner Industries of Cleveland, an aerospace company.

LEAD: * Banner Industries, Cleveland, a diversified industrial company, said it would sell its Thompson Aircraft Tire Corp. subsidiary for an undisclosed sum.