Seventeen Tu-144 were built in total, all of them until flight status except the last one that remained incomplete at VASO factory in Voronezh. There was one prototype (Tu-144 model), one pre-production aircraft (Tu-144S model) and fifteen production aircraft (nine Tu-144S models + six Tu-144D models). Only seven Tu-144 have arrived until today, two more were destroyed in both accidents, six were scrapped and two are in status unknown.

This is the list of the seven still existing aircraft and their current location:

• CCCP-77106: On display at Central Air Force Museum of Russia in Monino, Russia.
  
• CCCP-77107: On display as a monument in the centre of Kazan, Russia.
  
• CCCP-77108: On display in the museum of Samara State Aerospace University, Russia.
  
• CCCP-77110: On display at the Museum of Civil Aviation in Ulyanovsk, Russia.
  
• CCCP-77112: On display on the roof of the Auto & Technik Museum in Sinsheim, Germany.
  
• CCCP-77114: On display as a monument in a roundabout close to the main gate of the Zhukovsky air base.
  
• CCCP-77115: Can be seen during MAKS AirShow on display in the Tupolev's facilities of Zhukovsky, Russia.

The last ever flight of a Tu-144 was performed by the aircraft number 08-2, registered RA-77114, on the April 14th, 1999 with origin and destination the air base of Zhukovsky near Moscow. It was the last flight of the joint research program conducted by Tupolev, NASA and others US firms.

Currently, all remaining Tu-144 are preserved out of flight status, this means that the maintenance in the last years has not been the suitable one to put them in the air; corrosion, discontinued engines, lack of spares and old avionics are the main problems. Only the support of a big company or governmental funds can make this a reality.

Yes, first commercial service was made in December 26th, 1975 by aircraft 04-1, registered CCCP-77106, carrying goods and mail between the cities of Moscow and Alma-Ata. First scheduled passenger service was in November 1st, 1977 in the same route, the number of flight was SU499 and was performed once a week. This service was cancelled in June 1978 after the accident of the aircraft 07-1, registered CCCP-77111, during a test flight.

In the early eighties, when all technical problems seemed are solved, the economic and political crisis in the USSR produced a lack of founds for the project. On July 1st, 1983 the Governmental order number 461-169 settled the cancellation of the project and the usage of the remaining aircraft for scientific flights.

The Tu-144 had been involved in two accidents. The aircraft CCCP-77102 crashed in Paris in 1973 during a demonstration flight and in 1978 the aircraft CCCP-77111 made an emergency crash landing in Yegoryevsk during a test flight.

Forward canards of the Tu-144 were deployed during take-off and landing, and they gave extra stability to the aircraft at low speeds.

Although was planned equip the Tu-144D with thrust reverses in the outer engines, this never happened and the parachute was necessary for to stop the aircraft after the landing.

Yes, in a joint project with Tupolev and others US firms for the research of a supersonic transport of second generation, SST-2. The selected aircraft was the number 09-1, was re-registered RA-77114 and their former engines replaced by the engines of the Tu-160 bomber. In total 27 flights were performed between 1996 and 1999, when the project was cancelled.

No, the Tu-144 and Concorde have enough differences between them to say that they are not a copy. Both are airliners developed in the same time period, with a similar technology and with the same target. Taking in count that the aerodynamics laws are the same in every place is normal that both designs share some features, but some others very important features, like the shape of the wing, the position of the engines, the landing gear, the forward canards or air intakes are quite different.

The big manufacturers of airliners are focused today in the development of a very fuel efficient aircraft with green technology and high comfort standards. That means, big airplanes with great passenger capacity that reduce the cost per passenger and a new generation of engines based in low consumption and ecologic targets. Unfortunately these features are the opposite of a SST as we imagine today it has to be. Some space agencies like NASA or the Japanese Space Agency (JAXA) have developed studies and experiments looking for a new SST, but without real results. On the other hand, several companies in the aeronautical sector seem to be interested in a supersonic business jet, this market may be today the future for a SST-2.