The Wild Weasel concept was originally proposed in 1965 as a method of countering the increasing North Vietnamese SAM threat, using volunteer crews flying the two-seat F model of the F-100 Super Sabre; while the United States Navy primarily relied upon the A-4 Skyhawk.[6][7] While an effective airframe, the F-100F Wild Weasel did not have the performance characteristics to survive in a high threat environment.