From the back of the game box:
Space jockey is a single player, full color, action game designed to be played on the Atari Video Computer System or the Sears Tele-Game.
You are a Space Jockey at the controls of a highly maneuverable Attack Saucer, which appears on the left of the screen. A variety of enemy weapons and obstacles appear on the right and move toward your space ship. These include tanks, jet planes, prop planes and helicopters, which all fire at you. Additionally, there are balloons, houses, and trees that do not fire but are obstacles capable of destroying your Attack Saucer on impact.
Your objective is to shoot down as many of the enemy objects as possible, scoring as many points as possible, while at the same time avoiding enemy fire.
Initially you have a fleet of three ships available to you. For each 1,000 points you can score, an additional ship will be available to you.