The first flight a Boeing 737 makes will usually take it from Renton where it was assembled to Boeing Field – a short distance away – where the flight test facility is located. Here the jets will undergo production flight testing and acceptance testing before delivery to the customers. Given the rate of production, that means there will always be a lot of jets parked on Boeing’s ramp.

Last summer, when I was up the tower at Boeing Field, I had a good view straight along the flight line. Further up the ramp were the active jets while the spot closer to the tower (where there used to be a viewing area before Max problems meant Boeing needed to park jets wherever it could find space) tends to be used for jets that are likely to be stored for longer – planes that were going to a customer that went bust for example.