In reality the CJCS is not in the chain of command. He is an advisor to the President and nothing else. The Chiefs of Staff of all the Military Services are where the real command power is..
As the odious Wikipedia puts it...
” The chairman is the highest-ranking and most senior military officer in the United States Armed Forces[2] and the principal military advisor to the president, the National Security Council,[3] the Homeland Security Council,[3] and the secretary of defense.[3][4] While the chairman of the Joint Chiefs of Staff outranks all other commissioned officers, the chairman is prohibited by law from having operational command authority over the armed forces; however, the chairman assists the president and the secretary of defense in exercising their command functions”
He’s the representative of the President to the JCS and the titular head of that group, and outranks all other military officers. Interpret however you want, but if I was the AFCS I wouldn’t be running behind his back to the President to launch a pre-emptive air strike anywhere.