Before you take a look at the study done on the Fitness Flyer and Airofit machines it should be mentioned that when you climb on one of these machines you will feel yourself a bit strange. The machine may feel a bit wobbly and you can begin to worry if there is any sort of seat belt on the thing.
The American Council on Exercise (ACE) commissioned a study by California State University, Northridge on the Fitness Flyer and Airofit machines. The results of the research are the following:
Both machines develop the motion of a cross-country ski machine while the foot pedals are suspended from the frame and glide back and forth in opposition to the arm levers. Seven moderately fit men used the machines performing the fundamental movements which were proposed by the manufacturers. Variations at 120 beats per minute included high and low resistance (on the Fitness Flyer), high and low hand placement, short and long strides, and leaning forward and backward (on the Airofit).
The final results showed that the long stride burnt significantly more calories per minute than the short stride on both machines. The Fitness Flyer has resistance settings and when set on high, there was an increase in the number of calories used over no resistance on the Fitness Flyer.
However, even training with high resistance on the Fitness Flyer, there was virtually no difference between the two machines. This means that both the Fitness Flyer and Airofit would produce the same aerobic intensity at peak levels.
Neither manufacturer of the equipment claims that the user can improve the muscular strength on these machines. You can just tone your muscles. Also the upper-body muscle recruitment was reported during the forward and backward lean on the Airofit machine. The degree of upper body muscle recruitment on the Airofit was dependent on the height and size of the user because the foot pedals and arm levers are not adjustable to accommodate the differences in height. Both the Fitness Flyer and Airofit machines trained the muscles at the hip and the front and back of the thighs.
Both these machines are beneficial for improving muscular endurance but you won't gain strength using these types fitness equipment. Also it has been noticed that "an already-regular exerciser who wants to increase the aerobic capacity will most likely be limited by the Airofit and Fitness Flyer."