Been hearing/watching what looks like an AF Gulfstream or Lear Jet coming in for a landing at Hanscom AFB in Concord MA. (I live in the flight path about 15 miles away) I did a little flying and understand touch and go, so what I am wondering is does the military require a certain number of landings to coincide with number of hours in the air, or could this be a "student" pilot? The have been at it for about 45 minutes, and I see them headed east about every 4-5 minutes. Same markings. There he goes again, make that...