TU-144

This is the TU-144 by 'alshe'.

The Tupolev Tu-144 was the first commercial supersonic transport aircraft (SST). It was one of only two SSTs to enter commercial service, the other being the Anglo-French Concorde. The design, publicly unveiled in January 1962, was constructed in the Soviet Union under the direction of the Tupolev design bureau, headed by Alexei Tupolev. Technically, it was the Russian version of Concorde.
This aircraft is very difficult to control. I would not recommend it for someone who has just started out with X-Plane.

Concorde

This is the Concorde SST by 'tsanchez'.

Aérospatiale-BAC Concorde /ˈkɒŋkɔrd/ is a retired turbojet-powered supersonic passenger airliner or supersonic transport (SST). It is one of only two SSTs to have entered commercial service; the other was the Tupolev Tu-144. Concorde was jointly developed and produced by Aérospatiale and the British Aircraft Corporation (BAC) under an Anglo-French treaty. First flown in 1969, Concorde entered service in 1976 and continued commercial flights for 27 years.

This add-on is nice and easy to fly. It definitely gets the spirit of Concorde out. The downside is it only comes with one livery - the Air France one.

This is a image of the Concorde at its cruising speed and height