Coronavirus Flying Restrictions
It's a fast moving situation but at the current time, 17 Mar 20, neither the BHPA not the DHPC are imposing any restrictions on flying.
BUT, in the same way that you should conduct a risk assessment (I'M SAFE - Illness, Medication, Stress, Alcohol, Fatigue, Emotion) every time you go flying; you should now include the added risk from Coronavirus. Whilst the threat of transmission on the hill or in the air is minimal, you should consider the implications of having an accident: the additional burden that you could place on the overstretched emergency services, both for yourself and for others.
You might also consider the implications of travelling together in cars, and in taxis and on public transport (if there is any). Hitch-hiking is likely to become more difficult.
BHPA policy is here.