I wonder how the German planes were received at the time. The swastika has a long history before Nazism, but it seems heavily used by Nazis at that point:
On 14 March 1933, shortly after Hitler's appointment as Chancellor of Germany, the NSDAP flag was hoisted alongside Germany's national colours. As part of the Nuremberg Laws, the NSDAP flag – with the swastika slightly offset from centre – was adopted as the sole national flag of Germany on 15 September 1935.
The Nuremberg Laws mentioned straightforwardly created legal dehumanization, but it wouldn't really surprise me if a lot of people just said "not my problem" and didn't think anything of the swastikas at the time.
I also wonder if at this point, Germany had started focusing on producing warplanes. A quick search shows this chart, which indicates that they were already ramping up for war:
