Lanyon began gliding in his native Cornwall in 1959. He wrote: 'The air is a very definite world of activity as complex and demanding as the sea...The thermal itself is a current of hot air rising and eventually condensing into cloud. It is invisible and can only be apprehended by an instrument such as a glider... The basic source of all soaring flight is the thermal.'

The work seeks to evoke the complex experience of flight over the Cornish sea and landscape. Lanyon, a pioneer of post-war abstract art in Britain, died in a gliding accident in 1964.