 The McDonnell design was therefore reworked into an all @-@ weather fighter @-@ bomber with 11 external hardpoints for weapons and on 18 October 1954 , the company received a letter of intent for two YAH @-@ 1 prototypes . On 26 May 1955 , four Navy officers arrived at the McDonnell offices and , within an hour , presented the company with an entirely new set of requirements . Because the Navy already had the Douglas A @-@ 4 Skyhawk for ground attack and F @-@ 8 Crusader for dogfighting , the project now had to fulfill the need for an all @-@ weather fleet defense interceptor . A second crewman was added to operate the powerful radar . 
