Another interesting one, that has occurred to me this last week ...... we're under the flight / glide paths for several airports, Bristol, Cardiff, Brum, etc..They'm a long way up when they come over us - audible, but not at a nuisance level and forever criss cross each other ... anyway .. not unusual to see half a dozen in the air above us at all time s of the day and evening ... usually .... the last week or so yer's lucky to see one, and pretty infrequently

... just seen the first 747 in days ... usually several a day, plus all the smaller charter sizes .....
last time the skies were this quiet was when that volcano erupted