Dutch Telesale is an online supplier that has a surprisingly useful set of pages (top picture) on its site. These chart the length and wingspan of a range of aircraft, at various scales, in both Imperial and Metric measurements.
For example, a 1:24 Boeing 777-300 would be a whopping 121 inches (3073 mm) long, but at 1:500 it’s just a palm-of-the-hand 5 inches (148 mm).
There are some nice things for sale on DT’s site too, including a Herpa Wings 1:400 Airbus and DC-3 pair (middle picture), commemorating old and new airliners in Cathay Pacific's fleet. From Spark there is a tiny, yet beautifully detailed PininFarina Modulo concept car to 1:87 scale.
The Modulo dates back to 1970, yet still looks utterly futuristic, like a rocketship on wheels. It’s one of my all-time fave designs, not least for the slide-forward cockpit canopy (bottom picture). Wow - imagine something like this as a 21st century hydrogen-electric ecomobile, on sale in your downtown auto showroom. Gimme! Now!
You can visit Dutch Telesales here.