Under a project code-named Aquatone, the Lockheed Skunk Works, headed by the legendary Kelly Johnson, completed a design for a successor to the U-2 in the summer of 1959. Project Gusto was the decision program for the Agency where the Convair design was competing with the Lockheed design. The Skunk Works entry, which had evolved from A-1 (for "Archangel") to A-11 and then A-12, in turn evolved into the U.S. Air Force's SR-71.

The photo below depicts the vast design and concept changes between the sub-sonic U-2 product of Project Aquatone and the Mach-3+ SR-71 Blackbird product of Projects Gusto and Oxcart

Photo provided by Roadrunner Dick Roussell

Photo provided by Roadrunner Historian, Frank Murray
L-R
Chet Bohart, Cy Perkins, Francis Gary Powers, Sammy Snider, Tommy Birkhead, Ed Perry, E.K. Jones, William "Dad" MacMurray, William "Bill" Hall, Buster Edens, Jim Charbonneaux, Harry Cordes

A rare photo of the U-2 flying in Diamond Formation

This photograph, made in Europe in 1957, shows aircraft of the first U-2 detachment to be deployed for operational use in intelligence gathering. On this particular day four aircraft were flown on shakedown flights, with take-off and landing times that resulted in their being airborne at the same time. The pilots, experienced fighter pilots, took this opportunity to exhibit the U-2 to ground personnel in a fighter show formation - the Diamond.
Lead aircraft, Glendon (Glen) Dunaway; right wing, Jacob (Jake) Kratt; left wing, Carl Overstreet; slot, Carmine Vito. This undoubtedly is the first - - and only - - four aircraft formation flown in U-2 airplanes.