Letting them merge? Boeing and McD were essentially forced to merge by the Department of Defense post cold-war. So were Lockheed and Martin-Marietta, and Northrop with Grumman, etc. It was in the national strategic interest, apparently. Recommended reading: https://www.wbur.org/onpoint/2023/03/01/the-last-supper-how-...

Only Lockheed and Northrop are only ones making military aircraft. Raytheon and GD have long stopped.