The Avro 608 Hawk was a proposed two-seater fighter variant of the Antelope, which was planned to be powered by a Bristol Jupiter radial engine.

Although construction of a prototype began, it was incomplete when it was redesigned with a 540 hp (400 kW) Armstrong Siddeley Panther engine as the Avro 622.

[1] Following interest by Canadian Airways, who had a possible requirement for a mail plane, Roy Chadwick again redesigned the incomplete prototype to the Avro 627 Mailplane .

[1] The Mailplane was converted in 1933 to a high-speed test bed for the Armstrong Siddeley Tiger engine, the revised aircraft being known as the Avro 654.

[1] On return from Canada, the Mailplane was entered in the 1932 King's Cup Race, where it recorded the fastest speed of 176 mph (283 km/h),[2] although owing to the handicap system, it came 29th.