Subcompact Point and Shoot
Identified by their small lens, often corner-mounted instead of center-mounted, and point-and-shoot sensor size (typically 1/2.3"). These cameras are designed to be used without a protruding lens in one flat, compact package, which is an advantage when lenses that hit the ground first will be the first to go. All focus work and zoom (if present) work is done using internal mechanisms.
 Compact Point and Shoot
Identified by their inclusion of a larger zoom-capable lens with a lower F-number mounted at the center of the camera package, which opens out in front of the camera when turned on. Typical point-and-shoot sensor size (typically 1/2.3"). These cameras can be quite cheap, but the particular models that are being liquidated as old stock at a 30-50% discount, which are always the best buys, varies season by season. The >$200 expensive P&S are rarely worthwhile for AP, because their zoom capabilities, better interfaces, and larger batteries aren't usable in the air.
These point-and-shoot cameras attempt to have the look and some of the versatility of a DSLR by packing on a big zoom lens in a big body with a big battery and flash. This is a very poor idea for aerial photography needs, as these are still stuck with small sensors, the zoom will be useless with heavy vibration, and the other perks of this camera are unusable in the air, while still adding weight.
The official defining feature of the rapidly emerging market for mirrorless cameras is usually the possibility of interchangeable lenses without the additional bulk and weight necessary to create an optical viewfinder. The really important feature compared to an expensive point and shoot, though, is a sensor that may be ten times the size. More sensor area equals some combination of lower noise, faster, higher quality pictures. The tradeoffs are cost and depth of field. DoF is rarely relevant flying at altitude, as all the features in frame are at similar distances to the lens.
The traditional DSLR market niche evolved directly from old film SLRs for professional photography. These cameras use a mirror and a prism for the optical viewfinder, which adds bulk and dead weight, but like the mirrorless they produce great pictures. As the standard photographic format for the 2000-2010 decade, which has stable competition between vendors, these cameras tend to have more accessory products available cheaper than the new market for mirrorless cams.