The House Aviations Subcommittee yesterday approved a compromise measure that would reduce some federal regulation of the airline industry.

The compromise, worked out by some key Democratic and Republican members, broke a seven-week logjam in the subcommittee. It also substantially increased the chances that President Carter, who has supported a bill cutting back U.S. control of the industry, will have an opportunity to sign a measure this year.

However, the measure is much weaker than what the White House wanted and what the Senate passed. It also is more conservative in many respects than the policies and direction of the current Civil Aeronauctics Board.

The bill would allow each airline:

To add one new route in 1979 without CAB approval, but would enable each one to protect one of its existing routes from new competition. After the first year, the CAB would be directed to study the effects of the program and recommend any further liberalization. The Senate bill would allow each airline to add one new routes a year after that.

To cut fares by up to 25 percent without CAB approval the first year, and 50 percent thereafter, but would not allow the carriers any freedom to raise fares without board approval. The board itself has recently proposed allowing carriers to lower fares by 50 percent without its interference. The Senate bill would allow fare reductions of up 35 percent and increases of up to 5 percent without CAB action.

Both the compromise and the Senate version would streamline some CAB procedures, allow carriers more freedom to drop routes and provide subsidized air service to small communities for a ten-year transition period.

The House measure now contains a "sunset" provision which would put the CAB out of business at the end of 1982, although the federal subsidy authority would be transferred to the Transportation Department.

Approval was given the compromise by voice vote yesterday without any amendments. But some members including Rep. Allen Ertel (D-Pa., hope to strengthen the bill on the House floor. "It really isn't a regulatory reform measure at this point of any major consequence," Ertel said. He said he won't offer any amendments at the committee level "because there's been an agreement to get this bill intact" through it.

The measure lanquished in the sub-committee after the panel accepted a substitute measure proposed by Rep. Elliott Levitas (D-Ga.) which eliminated the key provisions of the bill as the subcommittee developed it throught extensive markup sessions. Levitas had the support of Republicans as a block.

The compromise measure was said to be worked out primarily by Levitas, Aviation Subcommittee Chairman Glenn Anderson (D-Calif.), Public Works and Transportation Chairman Harold Johnson (D-Calif.), and Reps. William H. Harsha (R-Ohio.) and Gene Snyder (R-Ky.).

White House spokesman Jody Powell said the administration was pleased that the subcommittee action advanced the bill, but said they would try to get a stronger bill on the House floor.