I live near Heathrow and just had a plane go over . I see about four or five a day . Last week it was all other airlines but now just BAI noticed a lot flight's over Europe, so googled why, I didn't find any reference to Coronavirus, but I found out that airlines often fly ghost planes to keep their take off and landing windows which they have payed for, and would loose if not used, I don't know if it is still going on during this crisis but it needs stopping at any time, common sense needs to prevail over money.