Today's New York Post reports the Department of Transportation has launched an investigation into a spike of near-collisions in the air over JFK, Newark and La Guardia airports. Those incidents have generated alarm as airlines predict a record summer for travel. Planes are supposed to be three miles from each other, but aircraft got as close as 500 feet on five occasions just in the month of May. Air-traffic controllers say they are understaffed and overworked all over the country. In the age of global positioning satellites, they have World War II-era radar to keep track of planes in the air. How much change is needed? How soon? Would moving too fast endanger a system that still boasts a remarkable record for safety?