Nathan Raab, left, and his father Steven Raab, talk about their recently discovered White House communications tapes involving Air Force One in flight from Dallas on Nov. 22, 1963, during an interview at their office, in Philadelphia, on Wednesday, Nov. 9, 2011. (AP Photo/ Joseph Kaczmarek)

Photo by: Joseph Kaczmarek

Nathan Raab, left, and his father Steven Raab, talk about their recently discovered White House communications tapes involving Air Force One in flight from Dallas on Nov. 22, 1963, during an interview at their office, in Philadelphia, on Wednesday, Nov. 9, 2011. (AP Photo/ Joseph Kaczmarek)