Complex sentence: These early studies envisioned a production run of 800 to 1,000 aircraft, and stressed maneuverability over speed; it also stated that the aircraft would not be considered without some level of ground attack capability.
Split into simpler sentences: These early studies envisioned a production run of 800 to 1,000 aircraft, and stressed maneuverability over speed. But it also stated that the aircraft would not be considered unless it had some level of ground attack capability.