Air defense only needed to disrupt the first wave

Hawaii had P-36 and P-40 fighters, dispersed airfields, troops able to guard aircraft, and roughly fifty minutes after the radar contact. P-36s made up about two-thirds of the available fighter force, with P-40s forming most of the remainder. Successful air defense did not require destruction of the raid: forcing torpedo and dive bombers out of coordinated formations would reduce accuracy and prevent them from overwhelming local defenses. The Hawaiian fighters could launch with ample local fuel, while the Japanese escorts were operating near the end of a long mission and still had to protect vulnerable bombers. The second wave had already launched by the time the first reached Hawaii, but it could have been recalled if the first attack met serious resistance. Even a limited interception could therefore change the first wave's results, make shipboard antiaircraft fire more effective, and alter the second wave's risk calculus.