Alighiero Boetti had always been fascinated by aircraft imagery, and whenever he came across images of aeroplanes in the newspaper he would make transfer drawings of their outlines. In 1977, Boetti pursued this interest further when he collaborated with Guido Fuga, an Italian architect and cartoonist, to produce a large-scale triptych depicting myriad highly-detailed aeroplanes, of varying design, scale and flying direction, teeming against a blue watercolour sky. Boetti was so enamored of this work that he photographed it and was then able to reproduce it, in varying sizes, with only the forms of the aeroplanes registering on the sheets. He would then have assistants fill in the areas surrounding the aeroplanes' outlines, in biro (ballpoint pen), ink and watercolour, resulting in a broad body of work known as the Aerei series. All works in the series are identical in composition, but Boetti allowed innumerable iterations and possibilities by altering the scale of the sheets and employing others to use varying colours and media to fill in the sky area.

The Aerei series encapsulates Boetti's interest in 'order and disorder' and 'bringing the world into the world', with fighter jets, passenger planes, Concorde, cargo craft, two-seater jets, and early propeller engines flying harmoniously, and impossibly, across infinite skies, conjuring an uncanny panorama in which the artist could obsessively classify all manner of aircraft. The planes hail from either the USSR of the United States and perhaps suggest Boetti's interest in subtle political critique through artwork, much like the displaced Afghan embroiderers would incorporate oblique political messages in Farsi in his Arazzi. Boetti was also a nomadic, intrepid traveler and often took flights to Afghanistan, Guatemala, Ethiopia, Japan, Morocco and Pakistan, deepening his fascination with air travel.

Aerei, 1989, is a large-scale three-panel work depicting Boetti's iconic fusion of aircraft, arranged neither by scale nor hierarchy, swarming amidst an infinite sky painted in thick, variable washes of brilliant azure ink.