Dr. Ludwig G. Lederer, 67, an expert on aerospace medicine and a former director of the medical clinic at National Airport here, died Nov. 10 in St. Louis, Mo., of a coronary embolism.

Dr. Lederer headed the airport clinic, which serves airline personnel and passengers needing medical attention, from shortly after he moved to the Washington area about 1940 until 1960, when he became medical director of American Airlines in New York. In addition to his work at the clinic, he also was medical director of the old Capital Airlines until it merged with United.

While at National, Dr. Lederer began a program to protect the hearing of ground personnel from the roar of turbojet and jet engines. While at American Airlines he began a program for alcoholics.

He retired from American last year and was in St. Louis on a consulting assignment at the time of his death. He lived in Stamford, Conn.

Dr. Lederer was a founder and former chairman of the sanitation committee of the Air Transport Association, a founder and past president of the Airline Medical Directors Association, and a past president of the Aerospace Medical Association.

In 1963, he received an award from the Aerospace Medical Association for contributions to medicine pertaining to airline pilots, and in 1969 the association gave him its Theodore C. Lyster Award for achievements in the general field of aerospace medicine. In 1974, he was honored by the Airline Medical Directors Association.

Dr. Lederer was born in Chicago. He did his undergraduate work at the University of Illinois and earned a medical degree and a doctorate in physiology and pharmacology from Northwestern University.

Surviyors include his wife, Kay, of the home in Stamford; four sons, Bert, of Honolulu, Jack, of Weston, Conn., Lyle, of Woodbridge, Va., and David, of Los Angeles; a daughter, Susan Torpey, of Roxbury, Conn., and eight grandchildren.