The Laté-299A is the Laté-299 n ° 01 modified with tandem engines and three-blade contra-rotating propellers. It flew 3 times (April 25, 27 and 28, 1944) before being destroyed on April 30, 1944 in Allied bombing.

The modification was made by SIDAL at the Latécoère plant in Toulouse-Montaudran. Engineer Wasseige is developing Hispano-Suiza 12Z engines (in reality Hispano-Suiza 12Y with new cylinder heads with 4 valves per cylinder). The nose is extended and the wings are moved down to make room for the second engine, while the cockpit is moved back to restore the center of gravity. The 12Zs lack reliability and do not provide the expected 1300 hp. They are therefore replaced by two 12Y-31s of 860 hp each. But the a/c is under-motorized (it weighs 5 tonnes) and its top speed goes from 500 to 400 km / h.

The Germans captured this a/c in November 1942, during the invasion of the free zone. They seized its interest and forced its completion, which was effective at the end of July 1943. It also bears German markings. Ground tests began at the end of summer 1943, but the aircraft was put on a pylon in February 1944. It was repaired in the spring and transported by road to Lyon-Bron. It is there that it makes its flights before being destroyed. It has long been believed that he never flew.