A thorough search of the ocean surrounding Long Island was conducted and turned up no signs of plane wreckage.
Nassau county police obtained an order from the U. S. Department of
Commerce, a week after the disappearance, to search every private, public and abandoned hangar on Long Island, covering the 100 mile stretch between Roosevelt Field, where he took off, to Montauk point, at the extreme tip of the island - the first of its kind.
Whitfield took off with only ten gallons of gas and there was a strong wind toward the sea at the time of the flight. It was considered possible, but unlikely, that he was blown to sea.
After Andrew's disappearance was discovered, an investigation discovered that, on the same day he vanished, he had checked into a hotel in Garden City on Long Island under an alias he occasionally employed: "Albert C. White." Hotel records indicated that Whitfield/White had paid $4 in advance for the room and never checked out. When the hotel room was searched, it was discovered that his personal belongings, clothing, cuff links engraved with his initials, two life insurance policies, and several stock and bond certificates made out in Andrew's and Elizabeth's names, were all left behind in the hotel room.
Phone records also indicated that he had called his home while his family was out looking for him, and a telephone operator reported that she heard him say over the phone, "Well, I am going to carry out my plan."
After this information was uncovered, police theorized that Whitfield had committed suicide by deliberately flying his plane into the Atlantic Ocean--although no evidence to verify this theory has been found. At the time of Whitfield's disappearance, there was no evidence that he was having personal or business problems.