Aerial Survey can be very useful in locating shipwrecks if the conditions are appropriate (clear water). The preferred tool for this is a balloon. Also useful are either a seaplane, helicopter or a light single-engine plane. When utilizing a balloon, it is tied to and towed by a surface vessel. In this manner, the position of the balloon can be controlled, and the towing vessel can stop and allow divers to investigate any suspected areas sighted from the balloon.
If a balloon is not available, a seaplane or a helicopter with pontoons will allow the explorer to land right over the suspected area and inspect it immediately, provided the sea conditions permit. When an aircraft cannot land at a target area, then it is advisable to have a surface vessel, which can be directed to the area from the aircraft. Divers can be sent down to investigate, or place buoys over the area to mark it for later investigation.
In the past, if you were operating alone in the air, it was quite difficult to mark the exact location, but with the advent of the modern GPS, it is quite possible that the location can be marked from the air (especially in a helicopter or balloon) with enough accuracy to enable investigation at a later time with a surface vessel.