Aside from the USAF, FedEx is the main recipient of aircraft coming off the 767 line these days. They have just placed another order too so they will continue to take new 767 freighters for years to come. One of the jets was planning to have a first flight at Paine Field. Prior to first flight, Boeing tends to run a high speed taxi and braking profile. If this goes well, they will then take off for the first flight. Judging by the radio traffic this time, things were not going well. They did one run, braked and vacated. They taxied down to my end and repeated in the opposite direction. Then they called the tower to confirm that they were heading back to the ramp. I imagine they fixed the issue before too long but no first flight on this occasion.