O2,
A flight review may not be conducted in a single place airplane. The purpose of a flight review is recurrent training on the ground and in flight, with an authorized instructor. Note that a ground instructor may endorse a student or applicant for the ground training portion of a flight review, but not the flight portion, as a ground instructor is not authorized to provide flight instruction. A flight instructor, by the same token, may not provide flight instruction on the ground; it must be provided in flight (otherwise, it's ground instruction).
Specifically, 14 CFR Part 61.56(a) specifies one hour of ground training, and one hour of flight training, at a minimum. 61.1(b)(6) defines flight training as "training, other than ground training, received from an authorized instructor in flight in an aircraft.”
Turning to 61.195(g), we find under "Position in aircraft and required pilot stations for providing flight training" that a flight instructor must perform all training from in an aircraft that complies with the requirements of 91.109. It further states that the aircraft must have at least two pilot stations and be of the same category, class, and type, if appropriate, that applies to the pilot certificate or rating sought.
91.109 provides an exception for aircraft with single controls, as opposed to dual controls.
There is no prohibition against performing the flight review in an experimental aircraft, but the aircraft will require at least two pilot stations.
