Since 13 May some sports, in which it is possible to observe social distancing, are permitted. The government takes the view that recreational general aviation is a permissible recreational sport.
This excludes most training flights, as social distancing measures require people not in the same household to maintain 2 metres of separation. While these flights are a key source of income for many aerodromes, they cannot presently be undertaken in a way that reduces the risk of Covid-19 transmission to an acceptable level.
Further additional information can be found here – https://www.gov.uk/government/publications/coronavirus-covid-19-recreational-general-aviation/coronavirus-covid-19-recreational-general-aviation