A unique array of flights during my lunch break at the north end of Boeing Field today (KBFI).
I didn't expect to see a Folland Gnat, that's for sure. I can't make out the tail number, unfortunately.
The second plane I found interesting was the Dornier 328-300, a type I'd never seen before.
Thirdly was the unmarked 737 that flew in. Only later did I found out that this is "Justice 43", N843BB, a jet that is used by the Department of Justice for prisoner transfers. I found more information about it at microvoltradio.com.