There have been a number of Aston Martin logos since the company started up in 1916. The first from 1920 was an amalgamation of the letters A and M. The next was inroduced in 1932 and the two wings were borrowed from the Bentley Logo signifying speed. The third was an evolution of the last and the design was gradually improved to keep up with modern tastes. It was modernised again to include the name “David Brown” in 1947 when he took over the company, lending his initials to several landmark vehicles in the AM range.
Roger from the Aston Martin Owners Club informed me that the above information is incorrect, and that the wings of the Aston Martin logo are actually a stylized representation of the wings of a scarab beetle from Egyptology.
From the Aston Martin Motor Club comes this image showing how the logo has changed over the years: