The aircraft finally entered production as the Aerostar 600 with two 290 hp (220 kW) Lycoming IO-540-K engines, first flown in December 1967.

The new company was renamed Aerostar Aircraft Corporation, and plans were made to move production to the Mooney plant at Kerrville, Texas, but Butler got into a dispute with American Cement over alleged corrosion problems with the airframe; the U.S. Federal Aviation Administration (FAA) investigated and found that no such problem existed, but the dispute resulted in a two-year production hiatus and cancellation of the plant relocation plan.

[1][3] In 1971, Smith attempted to repurchase the rights and announced he would be building an all-new design that was better than the Aerostar, but negotiations broke down.

[6][1] The Aerostar emerged as a mid-wing cantilever monoplane powered by two wing-mounted piston engines, with retractable landing gear in a tricycle configuration.

It is designed to seat six, and is distinguished from light twins of similar size and weight by its high wing loading, careful attention to fine aerodynamic details, a mid wing, and in early models, the absence of cowl flaps; Smith was adamant that they were not needed because of the refined cooling system design.

Despite this, the later 700P used cowl flaps because engine cooling of earlier models proved marginal if the system is not maintained rigorously.

Later models featured a redesigned turbo system intended to increase reliability and be more forgiving of improper operation by the pilot.

Light construction, low drag, and powerful engines contribute to fast climb rates, while allowing high operating altitudes and class-leading fuel efficiency.

To mitigate these problems, a 1984 airworthiness directive (AD) required owners to install individual, more accurate fuel gauges for each wing tank, a dedicated low-fuel warning light, and placards explaining correct crossfeed procedures.

A number of accidents have resulted from the upper half of the door coming open in flight and in some cases separating from the aircraft.

Although it was not conclusively listed as causal, an unsecured upper door is widely thought to have contributed to a 1988 crash that killed pilot and auto racing driver Al Holbert.