There are many great ones, but one should always be a bit careful with giving all the praise to one person.
Messerschmitt may have outlined the features of the Bf 109 and contributed with his vast knowledge in light constuction. But most of the actual design was done by Robert Lusser, who was also in charge of the Bf 110 and later the He 280 and He 219 (though those never reached their potential). Later, Bölkow was the one who introduced a lot of improvements to the initial design. By this time Messerschmitt was clearly more of a business, planning and strategy man, than a designer.
Kurt Tank likewise was already more of a leader by the time the Fw 190 was designed at Focke-Wulf. The men brooding over drawings and calculations were Rudolf Blaser and Andreas v. Faehlmann.
All aircraft are designed by many men,each with their own expertise.
I will cite the little known Spitfire as an example.All of these man had an input of some sort into the Spitfire or its construction.
Axtell,Black,Childer,Clifton,Conley,Cox,Davis E,Davis J,Dixon,Dickson,Eke,Elliott,Faddy,Fear,Fenner,Griffiths,Hammond,Harris,Hennessy,Holmes,Horrocks,Hughes,Houghton,Johns,Jupp,Kennedy,Kember,Kettlewell,Kimber,Knight,Labette,Lardmann,Lovell-Cooper ,MacFarlane,Mansbridge,Mansfield,Miles,Munro,Musslewhite,Noble,Rasmussen,Rice,Rodgers,Pardoe,Parry,Payne,Scales,Schlotel,Shenstone,Shirvall,Smith H,Smith J,Sommer,Walker,Weedy,Westbrook,White.
That's just the ones who worked directly for Supermarine. Some are well known,some less so. I didn't even mention Mitchell or the test pilots,Summers,Pickering and Quill. I could include men like Scott-Hall,the resident technical officer from the Air Ministry and all the other external personnel who contributed to or influenced the final design,but then I'd run out of space!
After the Me 210 debacle Willy Messerschmitt was forced out of his management/directorial roles and back to a more design based role by the RLM and particularly Milch who never liked him anyway.
Cheers
Steve