I used to work for virgin balloon flights in 06 and 07 as a part of the balloon crew and have registered here to hopefully clear up a few bits and give a little insight into ballooning in the uk. virgin operate their own balloons and pilots around the country rather than relying on smaller operators, most of the smaller operators are using smaller balloons and baskets which can carry fewer passengers at a time. going back to when I left there were around 20 balloons operational on a daily basis with around 30 flights scheduled each day (remember the same balloon can fly from one location in the morning and another in the evening) I would assume that the fleet has grown since then but even if you say it hasnt then at 30 scheduled flights per day the fleet could cover every launch site every 4 days. with the flights being scheduled months in advance the demand for a particular site can be judged and extra flights can be put on for the more popular launch sites where every flight is booked solid almost straight away and fewer flights from the less popular sites where the flights are not filling up (note a flight not being completely full wouldnt cancel a flight, it would just lead to slightly less flights in the next schedule) with regards to reasons behind cancellations.. there are a multitude of possible reasons for a cancelled flight, by far the most common is wind speeds (or in some areas wind direction) its worth remembering that the pilot is basing his decision on the forecast in the air rather than the forecast on the ground, these 2 forecasts can be quite different with little or no wind on the ground but high wind speeds in the air. others in the list would be a forecast for thunderstorms, rain, low cloud or mist/fog. other less common reasons for cancelling a flight can be a problem with the balloon itself or the vehicles needed to carry the balloon or passengers. during the season the crew and vehicles get very little downtime between flights so a problem at the end of a morning flight can easily lead to the evening flight being cancelled. one event from a few years ago that sticks in my memory was the 4wd and trailer with the balloon being sideswiped on the motorway which caused it to jack-knife (there wasnt a straight panel on the vehicle afterwards) this caused a large amount of damage to the trailer the balloon was on, we tried everything we could to get things together for the evening flight but there isnt anywhere in the uk that you can obtain a trailer with all of the extra equipment needed to carry and lift the basket with less than a couple of weeks notice, even though there are spare trailers within virgin it would have taken too long to get the trailer and shift everything over for the evening flight to go ahead. a problem with the balloon can take that balloon out of action for weeks at a time, this isnt because virgin arent capable of fixing the problem it is because they are not allowed to, the only people who can fix some problems are the 2 uk balloon manufacturers (Lindstrands in oswestry or Cameron in bristol) and these almost always have a backlog measured in weeks or months. even buying a new basket isnt an option since the lead times on those was normally in excess of 8 months for the size of baskets that virgin required