 “ It locks on the other plane ’ s transponders and tells the pilot whether to go up or down, ” John Hansman, aeronautics professor at the Massachusetts Institute of Technology, said by telephone.
<fluency>  “ It locks on the other plane ’ s transponders and tells the pilot whether to go up or down, ” John Hansman, aeronautics professor at the Massachusetts Institute of Technology, said by telephone.
 “ It locks on the other plane ’ s transponders and tells the pilot whether to go up or down, " John Hansman, aeronautics professor at the Massachusetts Institute of Technology, said by telephone.