Airplane/helicopter

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Aircraft heavier than air for flights in the atmosphere (and in space (e.g. Orbital aircraft)), using the aerodynamic lifting force of a glider to stay in the air (during flights within the atmosphere) and the thrust of the power (engine) installation for maneuvering and compensating for losses of total mechanical energy on air resistance. 

Rotorcraft, an aircraft in which the necessary lifting force and thrust are created by one or more lifting propellers driven by an engine or several engines. They are distinguished by maneuverability, ability to hover and almost vertical takeoff.

 
An ordinary airplane can be mistaken for a UFO even with an unusual angle of observation, when illuminated by sunlight at sunset or sunrise, when reflecting bright light from the Sun, and also in photos, especially if it does not leave a condensation trail behind.

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The movements of the aircraft are also used to calibrate NASA instruments.

The AeroCycle HZ-1 was built by the De Lackner company in the mid-1950s. Originally called the DH-4 Helivector, it was later renamed the HZ-1 Aerocycle and resembled a hybrid of a helicopter, a motorcycle, and an outboard motor.

The HZ-1 aircraft was equipped with a 40 hp engine, which was coupled with two coaxially arranged propellers. The propellers with a diameter of 4.6 meters rotated in opposite directions, which allowed the platform on which the pilot stood to avoid rotation. The pilot is positioned vertically directly above the rotating propellers. To control the aircraft, a handle similar to a motorcycle was provided. With its help, the pilot had to change the speed, direction, and altitude of the HZ-1 flight (to make a turn, it was necessary to tilt the entire aircraft in the desired direction - just as it is done on a motorcycle).

It was assumed that American military personnel would be able to effectively use this flying platform after only 20 minutes of briefing. But test pilot Selmer Sandbey, who tested the HZ-1, had a different opinion. In particular, he noted:

"One flight was enough for me to understand that an ordinary person will have a damn hard time dealing with this design."

All the identified shortcomings led to the closure of this program. At least one such flying platform has survived to this day and is exhibited as a museum exhibit.

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• Spaceplane - SC as the second stage of an aerospace system (ACS), launched into orbit not only by its own engines, but also with the help of a launch vehicle, and rocket boosters, or a winged 1st stage of the ACS during vertical takeoff or a plane-launcher or winged 1st stage of the ACS during horizontal takeoff. In systems with horizontal takeoff, the air launch technology is used to launch spaceplanes. In fact, one of the first spaceplanes in history to make suborbital manned space flights and for 20 years the only ACS was the American hypersonic aircraft-rocket plane North American X-15 of the 1960s (13 of its flights above 80 km (US norms), and 2 of them, in which the space boundary of 100 km (in accordance with FAI world norms) was exceeded, were recognized as suborbital manned space flights, and their participants as astronauts).
• Spaceship - a single-stage ACS that enters orbit by its own engines during vertical or horizontal takeoff. Due to the necessity of using significantly more advanced engine and structural technologies in creating spacecraft, none of the spacecraft projects have been realized by the present time. One of the first detailed ACS and spacecraft projects was the unrealized Zenger project (in the late 1930s) to create a partially-orbital combat spacecraft-bomber "Silberfogel" in Nazi Germany.

The MD 500 was developed based on the Hughes 500, the civilian version of the OH-6A Cayuse/Loach of the U.S. Army. Initially, the MD 500 was manufactured by Hughes Helicopters as the Hughes 500. Since its inception in 1967, numerous models have been produced, often with a more powerful engine or a five-blade rotor instead of the original four-blade equivalent. The MD 500 is commonly used for utility work, especially the MD 530F; it has also been popular among law enforcement agencies. McDonnell Douglas approved the production of the aircraft renamed MD 600N in March 1995. FAA measurements in the U.S. determined that the MD 600N is the quietest helicopter in the world.

In the book "Mirage Men: An Adventure into Paranoia, Espionage, Psychological Warfare, and UFOs," it is described as follows:

The exhaust of the "five-hundreds" was also equipped with a silencer, the air intake was provided with a partition, and the body was completely covered with lead sheets and vinyl gaskets. Full silence was not achieved, but the sound emitted by the machine changed to such an extent that it could not be recognized as a helicopter. And "Careless" came out not only almost silent, but also almost invisible: with the help of an infrared camera, the machine could fly and land without the use of lights... They were incredibly quiet; soldiers at the base said that when "Persistent" flew overhead, it sounded like a distant flying plane - such inconsistency was nerve-wracking when the helicopter was right in front of you.

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