What surprised me about the story was that the two F15s went supersonic (Mach 1.2-1.3) in the first place as they would have to had to have made a visual IFF interception against a slow small moving low altitude float plane quicker if they had flown the profile subsonic. The supersonic pass over Seattle made very little sense if they were indeed meant to intercepting a slow moving low altitude target especially as the F15s would have very little loiter time due to low fuel reserves.

Weird story.