Photographs taken from light aircraft might categorised broadly as exhibiting vertical or oblique composition. In general the type of composition is determined by the purpose for which an image is created.
Those taken with a camera looking vertically down at the ground are likely to be useful for mapping, photogrammetry and interpretation work. With this in mind, this type of work is often undertaken with calibrated, high-resolution, large format cameras mouted in the underside of the aircraft.
Images created from an oblique angle, perhaps with a hand-held camera angled down 20 degrees or 30 degrees, are known as oblique images. This description is sometimes subdivided into "low" or "high" oblique according to the height of the aircraft and hence the negative elevation angle. Most pictorial work falls in to the oblique category because it gives a better three-dimensional representaion of the subject, and the need for specialist equipment mounted under the aircrat is eliminated.
Oblique images often benefit from a good element of side-lighting so that form and depth are emphasised by the presence of shadows and increased contrast. This results in a somewhat richer rendering of the subject. For this reason, aerial images required for developers and asset management may be composed in this manner.
Composition for aerial photographs is essentially no different from ground-level composition. Images must be framed in interesting and creative ways if they are to stand out of the crowd. Choos angles that look interesting to a trained eye and take lots of photographs of a subject from different angles. Always remain aware of the angle of the light falling on subjects. Also, make sure that the verticals in an image remain vertical - ie parallel to the vertical edges of the frame.
Where possible, plan compositions before taking to the air. If the intended subject is a house or factory, consider what the best time of day might be to achieve the required result. Check whether the surrounding area is tidy etc.