McDonnell F-110B Phantom - Tactical Air Command, 1963
 
The resounding success of the F-4B in the competitive fly-off against the F-106 during ‘Operation Highspeed’ led to a more comprehensive evaluation of two loaned Navy F-4B’s (designated as the F-110A) but McDonnell had already been planning a purpose-built tactical fighter version of the F-4 for the USAF with manual terrain-following radar and TF30 turbofan engines. Designated F-110B this aircraft promised to be an excellent partner to the F-111A (TFX) and quickly gained the support of Defense Secretary Robert McNamara who authorised production of the type in February 1962. The pre-production prototype first flew in November 1963 and the F-110B entered service during the following year.