Future of Flight Museum (FFM) is a small aviation museum at Paine Field, Everett, Washington. It has a small collection, indeed, two other aviation museums at Paine Field have more flying planes than FFM has non-flying airplanes.
But FFM has two big pluses and a small one.
First, the Big View. FFM is across Paine Field from the Boeing flight line. It has a clear view of most aircraft from the time they come out of the big doors of the largest building in the world, while they get final preparations for flight testing, and every take off and landing, until the final take off to fly away to the customer. Believe me. If you are a "trust and verify" kind of person then take a look at KPAE Paine Field blog. Matt Cawby posts photos of aircraft at Paine Field almost every day. He takes his photos from the FFM parking lot. (I was hoping to meet him, but he wasn't on the geek tour.) And FFM has a third-story balcony overlooking the runway and flight line.
Second, The Party. Boeing's plant tour starts at FFM. Indeed, that is why FFM exists, in my opinion. FFM provides the parking, gathering area, theater, store and other necessities for hosting the public, restaurant, etc. So people from around the world come to see the Boeing production line and get to see FFM as a bonus.
Third, the small one. When Boeing wants input from the public they do their interviewing at FFM. So you might get the chance to have a very small input on Boeing's direction. I got a small flashlight that I used for years for one of these public feedback sessions.