"It was symptomatic of the agony in which the republican system found itself that no effort was made on the part of the more moderate political parties to nominate a candidate with a clearly identifiable party profile. For a while the SPD's Carl Severing considered nominating Hugo Eckener, who was widely known as captain of the airship Graf Zeppelin and was known to be a moderate liberal, but he changed his mind when the Hindenburg solution presented itself. The idea that the Reich president must not be a party politician was tacitly accepted by a majority of Germany's political parties This, in turn, reflected the pervasive antiparliamentary sentiments that now embraced even the parties of the bourgeois Left..." Hans Mommsen, The Rise and Fall of Weimar Democracy, p. 405. https://books.google.com/books?id=My6VNpvQlYIC&pg=PA405
POD: Hindenburg dies in early 1932. Eckener-Hitler presidential race? Eckener might get less conservative support than Hindenburg (though even Hindenburg had lost much of his right-wing support from 1925 and was now in 1932 dependent on the Weimar parties that had opposed him in 1925) but Hindenburg's majority over Hitler was large enough (over sixteen percentage points) that Eckener could lose a fair number of Hindenburg voters and still win. https://en.wikipedia.org/wiki/German_presidential_election,_1932
If Eckener wins, he is not likely to appoint Hitler Chancellor. "Eckener did not make any secret of his dislike of the Nazis..." https://en.wikipedia.org/wiki/Hugo_Eckener
POD: Hindenburg dies in early 1932. Eckener-Hitler presidential race? Eckener might get less conservative support than Hindenburg (though even Hindenburg had lost much of his right-wing support from 1925 and was now in 1932 dependent on the Weimar parties that had opposed him in 1925) but Hindenburg's majority over Hitler was large enough (over sixteen percentage points) that Eckener could lose a fair number of Hindenburg voters and still win. https://en.wikipedia.org/wiki/German_presidential_election,_1932
If Eckener wins, he is not likely to appoint Hitler Chancellor. "Eckener did not make any secret of his dislike of the Nazis..." https://en.wikipedia.org/wiki/Hugo_Eckener