He had begun to relax when another bright flash lit his cockpit. This time he had seen the that the light came from the north ahead of his plane. In the distance he saw a formation of dazzling objects skimming the tops of the mountains at extreme speed. Arnold assumed they were new jet fighters that the Air Force was just putting into service. Nine objects were flying in a tight echelon approximately twenty miles away. Every few seconds two or three would bank or dip slightly reflecting a blaze of sunlight. Their wingspan was judged to be 45-50 feet by Arnold. He timed them as they passed Mt. Rainier to determine their speed. It took one minute and 45 seconds for them to pass. The math worked out that they were traveling at 1,656 miles per hour, three times as fast as any known aircraft could fly.

Arnold landed at Yakima about an hour latter and told his associate Al Baxter the manager of Central Aircraft. Baxter called several of his pilots to hear the story. A theory that the objects were a salvo of guided missiles from a test range that was near. This theory did not account for the maneuvers (the banking and turning) that the objects did.

Later Arnold took off for Pendleton, Oregon were the news of his sighting preceded him. A group of reporters surrounded him at the airport. The questions he asked were doubtful as he told his story. He maintained his story eventually impressed even the skeptics. Arnold seemed to be a believable man; he was a successful salesman and an experienced search and rescue pilot. He had over 4,000 hours of flying time and flown through the Cascades before.

The sighting in the Cascades by Arnold provoked considerable scientific debate. One theory focused on the fact that at twenty miles the human eye is unable to distinguish objects of forty five to fifty feet. As the objects must have been much closer then Arnold thought they could have been a flight of jets flying a subsonic speed which appears incredible fast at close range. Another scientist said that since Arnold had used a fixed point, the mountains, as a reference point for determining distance the size of the objects was wrong. Most likely they had been bombers. The military would not confirm or deny if it had planes aloft in the Cascades June 24. They believed that what Arnold had seen was a mirage: the mountain tops seemed to float because of a layer of hot air.