Ancient Indians and the science of flying

[Narayan R. Joshi]

In connection with the etymology of the word Gandharva, one of the
participants of this discussion group remarked that Gandharvas knew flying
while Indians lacked the knowledge on the fundamentals of flying. The
book,"Brihad Vimanashastra" by the ancient sage Bharadvaja is well known to
Indologists. Could anyone please tell us the time period of this book? When
was it composed? Thanks in advance. N. R. Joshi.