Beechcraft Bonanza

 The Bonanza was introduced in 1947 and is still in production today, with over 17000 built. The aircraft is readily identifiable by its V shaped tail (with its two "ruddervators") This tail was changed to a conventional rudder and elevators in 1982.The retractable tricycle landing gear is also uncommon. 

The dealer, Field Aviation is also still around, not at that location but well known for their modifications of aircraft for specific purposes.

The the other company mentioned in the ad is Hunting Associates, of which I cannot find any information.