Only a few weeks ago I noticed 2 hot air baloons over London, very early on a sat morning, about 0600ish heading say, in a south-easterly direction(hard to tell from where i was) and they 'flew' right accross the approach to Heathrow at about '1000ft. From where i was(sat at Blackfrairs for a while then set off down towards Croydon/Brighton) they looked like they were just beyond the Eye/Houses of parliment heading towards Croydon. I also noticed that aircraft were stacking up in the various holds east of London and nothing was going in. This must have lasted a good 20 mins or so untill i eventually lost sight of them. Usually a good stream of traffic heading into Heathrow but everything stopped whilst these baloons made their way south. I was on the mobile talking to a controller i know who said they have priority over everything. I wonder how much they cost the airlines.......
