If you'll remember from the movie, Pearl Harbor, because the American planes at Pearl were destroyed on the ground, some pilots drove out to Haleiwa while the Japanese were attacking to secure some planes to engage the enemy in the air. They drove to the Haleiwa air field. Remnants of the air field 66 years later, can still be seen in the background near the shoreline. While the road to the airfield, the airfield and the inland parts are either government property or private property and off-limits, all beaches are considered public access in Hawaii up to the high-water line. In practice that is true at least where it is not adjacent to military land.