The Senate Aviation Subcommittee wrapped up 13 days of hearing of proposed legislation to reduce regulation of the nation's airlines, but may well schedule a few more days of testimony before markup of a measure begins.

At the close of yesterday's hearing, Aviation chairman Sen. Howard W. Cannon (D-Nev.) said Sen. Ted Stevens (R-Alaska) has asked the subcommittee to hold one or two more days of hearings on the special problems of Alaskan aviation before the subcommittee begins writing a bill.

"I don't think we will try to start a markup before two or three weeks to give us time to digest what we've heard and get a feel for where we're going," Cannon said. He added that he had "a lot of thoughts and a lot of ideas" but wants to review the record before he reaches final judgements on the features he believes the legislation ought to encompass.

Because "not too many members" attended the hearings, and there were "some decided differences" among those who did, Cannon declined to give a definitve target date for a bill's emergence from the subcommittee.

The House Aviation Subcommittee has scheduled one afternoon of hearings April 18 on proposals to alter the current air regulatory framework and then plans to resume hearings in May. Aviation chairman Glenn M. Anderson (D-Calif.) is working on a measure to introduce but is said to have not decided on its exact outlines yet.

After President Carter put his full backing behind the legislation last month, both Cannon and Anderson pledged to move a bill along through Congress as quickly as possible; it is already clear, however, that President won't get a measure on his desk for signature "by summer" as he had hoped.

At yesterday's hearing, Sen. Charles H. Percy (R.-Ill.) endorsed the measure co-sponsored by Cannon and Se. Edward M. Kennedy (D-Mass.). He said government regulation was retarding growth in the airline industry, harming the long-term interests of airline management investors and employees. "And most important, regulation is starting to price air travel out of the reach of too many Americans," he said.

Percy noted that United Airlines estimated that the average household income of pleasure travelers on its flights of an hour or more is $25,400, while the average family income is less than $15,000. A 1974 Gallup poll showed that 76 per cent of the population had not flown in the previous year and that 45 per cent had never flown.

In contrast, he noted that in areas where low-fare service has been made available because of less restrictive regulation - California, Texas and the charter markets - air travel has mushroomed. Noting that a number of studies indicates that air fares could be lower with less regulation over rates and entry, Percy said, "whatever justification there once was for regulatory pateralims, it exists no longer."

Percy said most airlines oppose moves to reduce regulation because they have become "comfortable with the Civil Aeronautics Board sitting as kind of a 'super board of directors' for its operations.

"But the fact remains that overregulation is choking off corporate innovation and the freedom to compete, and is jeopardizing the viability of dynamic private industry," Percy, a former businessman said. He added that he was "rather shocked" to hear that American Airlines wants the CAB to regulate the now unregulated scheduling of airplanes by controlling the number of flights on each route.

Using Illinois as a case study, Percy attacked some of the claims the carriers are making in defense of the current system:

Service to smaller communities will be reduced under less regulation. Percy said the major carriers have been steadily pulling out of medium and small sized towns since 1940 and now make "few" small-town flights.

Employment will go down. Job security has been elusive under regulation, he said, noting that there were fewer jobs in the industry in 1976 than there were in 1973. "I am of the belief that, if anything, overall employment in the industry will increase as new, innovative low-fare services attract the three-fourths of our population that does not regularly fly."

Carriers will find it even more difficult than it currently is to get money to finance new planes, "profits" is what brings in capital, he said, noting that the "extraordinarily well run" Braniff Airways was able just last week to get $80 million in credit from 20 banks at the prime lending rate.