Back in the 1980's I participated in a series of wind tunnel tests in connection with an aircraft project. (I wrote about it in Weekend Wings #40.) They were fairly primitive by today's standards: hand-crafted models, some made of wood, some of clay, a few of metal, suspended by various means (including fishing-line and baling-wire) from the top, bottom and sides of the apparatus, and measured by means of smoke trails blowing back in the slipstream. Things became more sophisticated later on, but by then my involvement in the project had ended.
I was therefore very interested to see this video clip of wind tunnel tests in the Netherlands on the design of the new Embraer KC-390 tactical transport aircraft, which is under development for Brazil's Air Force and other customers. It'll be the biggest aircraft Embraer's ever produced, a rival to the venerable C-130 Hercules with similar cargo capacity, but much greater speed. I think it has every prospect of success.
Aviation enthusiasts will learn a lot from this video, with particular reference to how lasers and other modern technology have transformed the measuring process. It's worth watching in full-screen mode.
I wish we'd had toys like that to play with nearly thirty years ago, when I was doing similar things . . .