Ba.15 c/n 1402 is probably a, or the, prototype as it was allocated military serial MM111. Three-digit MM serials were for prototypes, also of civilian types, and evaluation or experimental aircraft. Colombo S.53 engine. Photo from: Flight

A motorcycle of the air, designed by Dutchman Frits Koolhoven for British Aerial Transport and powered by an ABC Gnat aero engine of 40 hp. The sole example never carried a registration. Performance was poor and handling 'too tricky' according to Flight. The journal suggested that it drew attention mainly from women and boys at the 1920 Olympia Aero Exhibition, while men knew better. In the background is a BAT FK.26 Commercial airliner, G-EANI. Photo from: Flight

Checking with the GAVS database of Italian serials, I worked out that the serial must be MM55004, and only then I saw that Dan Shumaker also has it as MM50004. This was the fifth in a large batch of 250 AS.1 trainers for the Italian air force. Photo from: Dan Shumaker collection

The Ro.5 sport aircraft was built 'in large numbers', also for the Italian air force. Despite the fasces roundel, this seems to be a civilian plane. I-FIDO is listed as a Ro.5bis but the Ro.5bis had enclosed cockpits. Photo probably taken before the opening of the Aero Show at Olympia on 16 July 1929. It appeared in the Flight edition of 18 July. Photo from: Flight