McDonnell Douglas Corp. earned $83.5 million or $2.18 per share on revenues of $3.720 billion in the third quarter of 1988 compared with earnings of $80.3 million or $1.98 per share and revenues of $3.226 billion a year earlier.

Net earnings in the first nine months of 1988 were $205.1 million or $5.34 per share on revenues of $10.441 billion, compared with $220.4 million or $5.43 per share on revenues of $9.796 billion a year earlier.