text: it is not necessary for any airplane 
  to fly supersonic over or adjacent to a popu- 
  lated area to create a sonic boom. This 
  possibility is shown by the second illustration 
  of figure 6.14 where an airplane decelerates to 
  subsonic from a supersonic dive. As the air- 
  plane slows to subsonic from supersonic speed, 
  the airplane will 
  release the leading bow and 
  tail waves which formed as the airplane accel- 
  erated from subsonic to supersonic speed. The 
  release of these shock waves is analogous to 
  the case where a surface ship slows to below 
  the wave propagation speed and releases the 
  then travels out ahead of 
  bow wave which 
  
  Actually, 