Play word association with Seattle and most people will come up with a combination of Nirvana, Hendrix, Starbucks and maybe rain (thanks, Frasier). But the list should also includes aviation, because Seattle is home to Boeing, and is one of the few places in the world where the public can get to see a commercial airliner being built. That might sound like watching paint dry (and, if you’re lucky, you might be able to see just that) but for anyone who loves what Steve Miller called big ol’ jetliners – or those who still can’t comprehend how those monsters can get off the ground – it’s a fascinating 90 minutes.

Forty minutes’ drive north of the famous Space Needle is the Future of Flight museum, which, more importantly, is the access point for the Boeing Factory Tour at Everett. And it is just that – a chance to stand in the largest building by volume in the world and watch the planes you might have flown across the Atlantic on being assembled. Illuminated by one million lights bulbs, it is the size of 55 football pitches (Boeing does love stats) and left to its own devices it has its own weather system, with clouds forming and rain falling thanks to condensation from the breath and perspiration of workers. Giant ceiling fans prevent this, but the warmth generated by bodies, lights and machinery means no heating is needed in this enormous shed.

The tour begins with a preliminary briefing (mainly – no phones, no photos, no fooling about) before visitors are allowed onto the factory floor (well, on balconies to one side) to watch shifts put together the 747, the 777 and the 787 Dreamliner. The number “7” prefix, by the way, indicates it is a jet aircraft, not a prop plane, a boat/submarine or, indeed, a spaceship.

       The sleek Dreamliner is assembled like a giant Airfix kit from components produced across the globe. The carbon/polymer resin fuselage comes over from Italy, the engines from the UK, and eight other countries contribute parts. Completed planes have to be towed over a bridge that crosses a busy highway to reach the Everett Field runway for their first test flights. This is now done at the dead of night – during daylight, drivers below were either alarmed to see a very, very low flying aircraft or slowed to gawp, and accidents were not uncommon. 

        The long line of partially completed 787s was certainly impressive – and there are yet more trundling along a similar production line at a sister plant in South Carolina – but it was the sheer size of the sole Jumbo on display that day that still inspired genuine awe. The one I saw was being lined up for final assembly prior to painting (which can add 1,000lbs to the weight), still clad in a protective green skin.

Boeing is down to producing just one Jumbo every other month as the order books switch to the 787s, even though the current 747 is much lighter and more fuel efficient than the original. Which is a shame, because I have a soft spot for it, being the first plane I flew to the USA on (who was it, when asked why they always preferred to fly on four-engined planes, replied “because they don’t make one with five”?). Speaking to the BA cabin crew about their favourite planes on the return trip this time, one them said that, despite its age, the majority of staff still love a Jumbo.

The coffee and the rain will always be there in Seattle, but the 747 will soon go the way of Cobain and Hendrix. Best get your skates on if you want to see this BFG of the skies being put together. 

* The Boeing Tour (001 425 438 8100/futureofflight.org) is at Everett Field and costs £16.30 for adults, £11.50 for 15 and under. Holiday Autos (020 3740 9859/holidayautos.co.uk) has seven days’ car hire from £27 per day. If you aren’t renting a car, Viator (020 3318 0421/viator.com) has tours with transportation from downtown Seattle from £54pp. British Airways (0344 493 0787/ba.com) offers return flights to Seattle from London Heathrow from £640. Virgin Atlantic (0844-573 0088, virginholidays.co.uk) will start flying the route from May 1, with similar prices. Further details at Visit Seattle (www.visitseattle.org) or www.Seattle-WashingtonState.co.uk.