No 6. Northrop Tacit Blue

Before you start laughing, do understand that this aircraft was a pioneer in stealth technology. There was only one produced, by the U.S. Air Force, in 1982, which was meant to demonstrate that a stealth low observable surveillance aircraft with a low probability of intercept radar and other sensors could operate close to the forward line of battle with a high degree of survivability. The pioneer plane is currently housed at the National Museum of the US Air Force.

No 5. Airbus Beluga

Beluga or the Airbus A300-600ST, is a transport aircraft resembling the Beluga whale. Manufactured by EADS (Airbus S.A.S.) as an Outsize cargo freight aircraft, the Beluga is actually is a version of the standard A300-600 wide-body airliner modified to carry aircraft parts and over-sized or awkward cargo.

[youtube]http://www.youtube.com/watch?v=9FDNcp__dE0[/youtube]

No 4. Kalinin K-7

Designed by Soviet Union during the 2nd World War, this monster aircraft, also known as the Russian flying fortress, was a heavy experimental aircraft tested in the Soviet Union in the early 1930s. This flying fortress had a wingspan of 53 meters.

[youtube]http://www.youtube.com/watch?v=6C_8GGhY6kA[/youtube]

No 3. Horten Ho 229

Designed by Horten brothers of Germany this plane was a late-World War II prototypefighter/bomber. Its odd shape can be attributed to the fact that it was designed to be more difficult to detect with radar. Horten Ho 229 never made it to actual war and was only flown as a prototype.

[youtube]http://www.youtube.com/watch?v=vGpRbUV3Sks[/youtube]