separation in the skies breached. the faa s latest numbers show planes came too close nearly 4400 times in one year. 41 of them deemed high-risk events. they are scary and unacceptable but there s a back-up system and people are safe. reporter: it s an air traffic system under stress. increasing air traffic and a potential shortage of controllers. almost thousands need to be hired and trained over the next seven years. some experts worry the agency s new hiring practices could make matters worse. the agency no longer gives preference to recent graduates from aviation colleges. just last month, a government auditor said he would study controller staffing levels and the impact of retirement. but incidents where planes get too close are not necessarily controller mistakes. this could occur through a controller making an error,