I am software developer since 40 years, and i grew up with fortran, pascal, c, c++, c# and some more. I am developing (windows) business applications against linux database servers and never used java and python because of performance (and many other) problems. I use c# with business libraries (DevExpress).
BUT c++ is in my opinion the absolutely best choice to get this performance of aerofly. You will find enough benchmarks and comparisons in the internet, and java and python are _much_ slower and for me no useful languages for this purpose, i think, ipacs uses the best language for their sim.