Senate Aviation Subcommittee chairman Howard W. Cannon (D-Nev.) said yesterday he is developing new legislation to reduce regulation of the airline industry - a move he said is necessary if the nations is to keep the airlines from going "the way of the railroads."

Cannon said his new proposal will race a greater emphasis on transition and moderation during the first few years as the airlines and the Civil Aeronautics Board adapt to a more competitive system than a proposal he had introduced earlier this year with Sen. Edward M. Kennedy (D-Mass.).

In hard-hitting speech to the Aero Club, whose members are connected to the air industry, Cannon twitted the airlines for the "shrill tone" of their predictions of doom that accompanied their opposition to significant change in the aviation regulatory structure during the three weeks of hearings he chaired.

Although he had heard for years from them about "the evils of CAB regulation," the law created the board was "sanctified and annointed so often and so profusely" during the hearings that he began to have the feeling that "Moses brought it down from the mountain as footnotes to the Ten Commandments," he said.

"It is interesting that businessmen usually decry governmental interference and regulation of business activities except in cases where such governmental interference gives them a competitive advantage or an opportunity to be lazy and rest on their oars," he said. "Businessmen in the airline industry have said loud and clear that they want as little free enterprise as possible . . .

"But protection of narrow competitive interests is a luxury we can no longer indulge," he said. "It is wasteful, it is inefficient, it is expensive. In the long run, it serves neither the airlines nor the public."

Under the proposal he is drawing up to remove the CAB's protective hold over the airlines, Cannon forsees a gradual lessening of regulation and movement toward more competition. In the area of new entry, for instance, he would require applicants for new authority to demonstrate that their proposed service is consistent with the public convenience and necessity; after three years, the burden would shift to those who oppose an application for new authority to show that it is not consistent with the public convenience and necessity.

Existing carriers would be able to add to their systems in a modest amount each year, but smaller carriers may be allowed more protection of their routes than larger carriers, at least for the first three years.

Cannon would also allow the CAB more regulation of air fares at the start of the transition.