The central reason the Soviet Union so actively attempted to revise the Treaty of Versailles (even if that meant empowering a nation that would almost certainly return one day under arms) was because the Soviet leadership viewed the Versailles framework as a limitation on their own revisionist goals on the world stage; this was essentially the same position that the leadership of Germany had as well even before the National-Socialists came to power. The Lipetsk School (which was, just to clarify, German aviators training German aviators on Soviet soil for the most part), was an expression of that joint revisionism during the Interwar Period. When Lev Trotsky and his Bolshevik negotiators signed the Treaty of Brest-Litovsk with the German Empire in 1918, a third of the population of the former Russian Empire alongside about 150,000 km^(2) of territory was lost at a pen stroke; this territory included significant industrial and natural resources as well. All of that was compounded by the fairly sanctimonious indemnity payments foisted upon the Bolsheviks by the victorious Germans. As a brief aside, it always baffles me when people denounce Versailles as some kind of overly punitive Carthaginian peace considering the terms imposed by the Germans when they still thought they were going to win the war were more severe by several orders.

A year later in 1919, when the Treaty of Versailles was signed between the Germans et al and the French et al, the Russian Soviet Federative Socialist Republic (RSFSR) was not even invited to the negotiations. Keep in mind that this was also occurring against the backdrop of an Anglo-French-American armed intervention in Russia on the side of the Imperial loyalists (called the Whites), in explicit opposition to the revolutionaries (called the Reds)^([)^(1)^(]). As such, the Soviets (quite rightly) viewed their exclusion from the new world order (and invasion by those in control of it) as the formation of a new paradigm which they required to be modified if their own international goals (i.e. world revolution) were to be attained.

The German Reich (more commonly called the Weimar Republic after the city in which the parliament assembled) and the RSFSR both renounced their financial and territorial claims against one another with the Treaty of Rapallo in 1922 about six months before the Russian Civil War was resolved in favor of the Reds. Diplomatically, Germany and Russia were in similar situations-- both were isolated on the world stage; militarily and economically, their relationship was complementary. Germany was an industrialized nation which was largely unravaged by revolution or world war but was prevented (by the terms of Versailles) from establishing any kind of serious military which might threaten their neighbors once more (this included an outright ban on an air force, for example). Russia was an industrializing (but largely not industrialized) nation which had been severely impacted by revolution, civil war, world war, and then a series of additional, smaller wars and revolutions which occurred in former Russian Empire territories that the Bolsheviks prosecuted in order to retain a certain amount of regional hegemony.

Because of this disastrous dichotomy of misfortunes, Germany and Russia were pushed towards one another which eventually, though not immediately, formed one of the most destructive political axes the world has ever known. Now, that sentence is not an attempt to incriminate or exonerate either party in their complicity concerning the mass carnage and destruction that was unleashed by the Second World War-- but it accurately reflects the reality of the situation in the world at the time. The rest of the world behaved just as quixotically towards the German state during the Interwar Period as well, but this is a question about the Soviet Union specifically.

With respect to the Lipetsk School though-- which operated from 1926 to 1933, it allowed the German armed forces to remain only slightly handicapped by their own lack of an air force because they were able to maintain research and development as well as training facilities beyond their own borders, thereby not officially breaking the terms of Versailles (though I think any legal scholar would say this was absolutely a violation of the treaty, especially given later German action explicitly violating the terms of the treaty). Lipetsk benefited the Soviets because, from their side of the quid pro quo relationship, they were able to gain access to German industrial facilities and intellectual property in exchange for turning a blind eye to early German rearmament. By the time Hitler came to power, the Communists in the Soviet Union recognized they may be playing with fire a bit too recklessly should they continue to facilitate German rearmament and they disbanded the Lipetsk facility in September 1933 (about 10 months after Hitler's appointment to the German Chancellory in January of the same year).

From exile in Turkey, Lev Trotsky diagnosed the growing National-Socialist phenomena as the logical conclusion of bourgeoisie-capitalist society (hyper-nationalism, ethnic chauvinism, close government and industrial cooperation without the socialist-preferred command-style economy, the intersection of human innovation and religious faith, etc.). He (and the rest of the Bolsheviks and largely the rest of the world) failed to recognize Hitler's political science for the unique and singular evil that it was. From Trotsky's What is National Socialism? (1933)^([)^(2)^(]):

Today [...] there lives alongside of the twentieth century the tenth or the thirteenth. A hundred million people use electricity and still believe in the magic power of signs and exorcisms. [...] Despair has raised them to their feet [and] fascism has given them a banner. Everything that should have been eliminated from the national organism in the form of cultural excrement in the course of the normal development of society has now come gushing out from the throat; capitalist society is puking up the undigested barbarism. Such is the physiology of National Socialism.

Pretty powerful stuff.

Despite Trotsky's eventual downfall and assassination at the hands of Iosef Stalin in 1940, the latter approached Hitler's German Reich with a similar point of view. The Manichean perspective with which Stalin approached the world stage postulated that Soviet conflict with capitalist society was inevitable (and indeed, ongoing) so therefore any bloodletting which Stalin could provoke amongst them was a net win for the USSR. Of course, this was also the Manichean perspective of the British and French who entertained treaties with the Soviet Union while simultaneously keeping them at an arm's length and negotiating with Adolf Hitler's representatives as well, but again, from the Soviet perspective, Hitler's logical trajectory pointed west (despite his shrieking about Liebensraum, the Slavic Untermensch, Judeo-Bolshevism etc). This theory was expressed by the Molotov-Ribbentrop Pact which saw the resumption of military and economic cooperation between Germany and Russia and of course eventuated in the Operation Barbarossa which saw the two nations at war once more.