KANSAS CITY, Kan. (AP) — General Motors is planning a celebration next month at the Fairfax Assembly Plant in Kansas City, Kansas, to mark the completion of its 500 millionth vehicle globally. The auto maker says GM CEO Mary Barra and North America President Alan Batey will be on hand May 4 for a news conference. The Fairfax plant builds the Buick LaCrosse and the Chevrolet Malibu. The plant has about 3,900 hourly and salaried employees and recently completed $600 million in improvements, including a new paint shop.