Derived from the abortive Ju 89 strategic bomber, it was developed to be used as a long-distance commercial aircraft for the German flag carrier Deutsche Luft Hansa.

It drew heavily upon the Ju 89, sharing the same wing and tail unit while adopting an all-new fuselage that could seat up to 40 passengers.

This aircraft, which had commenced developing during the mid-1930s, was a contender in the Ural bomber programme that was aimed at creating a long-range strategic bombing capacity for the Luftwaffe.

[3] By the time that the Ju 89 programme had made it through to the flight testing phase, the development of four-engined bombers had become an increasing politically contentious matter, particularly following the untimely demise of General Wever (one of the programme's most powerful advocates) as well as rising tensions between Erhard Milch (another proponent) and commander-in-chief of the Luftwaffe, Hermann Göring.

[4] Accordingly, while the aircraft retained the wings and tail unit of the Ju 89, it also incorporated an all-new fuselage that was considerably wider and suitable for the carriage of passengers.

[5][6][7] This new rectangular section fuselage was primarily constructed of duralumin along with some steel elements,[8] was relatively generous by the standards of the time, possessing an internal width of 2.83 m (9 ft 3+1⁄2 in).

[citation needed] In terms of its basic configuration, the Ju 90 was a four-engine all-metal low-wing aircraft fitted with twin end-plate vertical stabilizers.

[11] The fins and rudders, the latter with prominent horn balances assemblies, were placed at the end of the tailplane; this latter carried the elevators separated by a gap, forming another double wing.

The rudders and rear portion of the elevator of the prototypes were the only part of the aircraft to use the traditional Junkers corrugated skin; all other areas had a smooth duralumin covering that was flush-rivetted.

[4] On 28 August 1937, the first prototype, the Ju 90 V1, performed its maiden flight;[4] it was powered by four Daimler-Benz DB 600C liquid-cooled inverted V engines, each one capable of producing up to 820 kW (1,100 hp).

Akin to the following production standard commercial Ju 90, this aircraft was powered by four BMW 132 radial engines delivering 620 kW (830 hp).

[11] The move towards lower power has been speculated to have been necessitated by the demands on Daimler Benz to produce engines for strategically important front-line aircraft.

South African Airways (SAA) opted to order a pair of Ju 90A-1s, powered by four Pratt & Whitney Twin Wasp engines that could produce up to 670 kW (900 hp) each.

The landing gear was strengthened with twin main wheels and the fins were more rounded, lacking the characteristic horn balance nick of the earlier models.

A special feature of both the V5 and V6 was a powered boarding ramp in the floor of the rear section of the fuselage for loading cars and larger cargo freight.

[14][12] Operated as part of the Luftwaffe's transport force, they were deployed to the Eastern Front for a time to help supply the German 6th Army that was besieged at Stalingrad.