The single-engine XF9F-2 Panther didn't just spring out of the fountain of Grumman's preliminary design team. The Navy inspected the mockups for the two prototypes in January 1946. The first flight was conducted on November 21, 1947. Because Grumman had declined the Navy's requirement to ship the Panther prototypes to the long runways of the Naval Air Test Center at Patuxent River to make their first flight, the Navy insisted that the first landing be made at the yet unfinished Idlewild (now JFK) airport's 8,000 foot runway, which took the new protype over the densly-populated suburbs of New York City in a first and newly completed jet fighter.