Björn Andreasson was wartime designer at AB Flygindustri sailplane works. In 1944 designed and flew BA-4 ultralight biplane, updated as BA-4B for home construction. In 1950s in San Diego (USA) designed and flew BA-6 low-wing single-seater and BA-7 shoulder-wing side-by-side sport/trainer, later produced as MFI, later Saab MFI-9/Safari/Supporter. Following BA-11 200-hp aerobatic biplane, Andreasson joined Malmö Flygindustri as chief designer.