True Ornithopter
- Main article at Ornithopter
People have been trying to make flapping-winged craft for a century and a half with little success, but lightweight materials, robotics, and electronic stabilization capability has recently made this borderline practical; The first human-powered design just recently flew (compare to human-powered fixed wing, which first happened in the 60's), for a very short test period. Unfortunately, ornithropters remain a fringe design because of a lack of demonstrated superiority to fixed wing and helicopters in any task, and big problems with efficiency, payload fraction, and stability in comparison.
On some level, birds have an extremely efficient mechanism of flight in a small form factor; The vast difference in mechanism between what motors are capable of and what bird wings are capable of, however, allows only very crude representations and control.
The practice of incorrectly calling a ducted fan bicopter (or tricopter) an 'ornithropter' appears to date to David Lynch's Dune, where the artists couldn't come up with a way to represent flapping wings.
- AeroVironment Nano Hummingbird is among the first to demonstrate decent control and helicopter-like flight times.
- XUAV Cybird X
 Flying Propeller
Any design where the entire craft needs to spin in a circle to achieve lift. Can be considered a curiosity for studying rapid-response control systems, as every adjustment in the flight path needs to be timed to hit at the correct part of the cycle, and cycled on and off, while the active sensors spin and solve for what they're seeing at a high rate of speed.
Controlled flight is best exemplified by Jack Crossfire's heroic efforts on the Marcy project, which uses a large weight-balanced blade with a small prop making it pinwheel, without any non-rotating part relative to the room.
- Note: This is distinct from the 1-bladed helicopter, which has a non-rotating fuselage
 Fan Wing
Replaces the leading edge of a wing with a cylindrical centrifugal fan rotor. Appearing to be a product of one designer's obsession, the fan wing surprisingly flies pretty well, but without demonstrated superiority to fixed wing craft at this time.
 Flippered Blimp
The Air Swimmers line of RC toys uses helium blimps without any propeller; They use a single-joint articulated tail in a flapping motion, and a weight-shift forward battery on a track, in order to navigate indoors silently with a remarkable degree of precision.