The US Navy had already begun to explore a companion aircraft to the F111B before that programme was cancelled. Faced with a shortfall in fleet defence capabilities as the Phantom aged, they instigated a crash programme to procure a new fighter. And although Grumman were clearly the front runners, they were not the only game in town.

This video explores the VFAX and VFX programmes and summarises the Navy's alternatives to the Grumman 303.

Main Sources:

Although I referenced several F14 books in the making of the video, Crowood Press' "Grumman F14 Tomcat" by David Baker is in my view the best single volume on the type. Although it is now an expensive book to buy, it is worth it if you're really interested in the F14

Tony Buttler's "American Secret Projects: Fighters And Interceptors 19451978" is in an updated edition and an exceptional purchase. It is understandably a little light on some details of the VFAX/ VFX competitors, but still useful

As ever, there are a wealth of brilliant Secret Projects Forum threads on this topic. Here are a selection:
NASA LFAX4: https://www.secretprojects.co.uk/thre...

Overall thread on the competition: https://www.secretprojects.co.uk/thre...

Vought V484 https://www.secretprojects.co.uk/thre...

Vought V505 and V507 ​​https://www.secretprojects.co.uk/thre...

Convair 44 https://www.secretprojects.co.uk/thre...