Re: In the air?

Date:         24 Mar 98 11:38:45 
From:         Andrew Cruickshank <>
Organization: OpenKast Limited
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Pete Mellor wrote:
> The following is a query from my friend
> Felix Redmill <> :-
> > I am told that at any one time two thirds of the world's civil aircraft are
> > in the air, and that this is necessary as there is not room for all of them
> > on the ground. Is this so? If it is, it will be interesting if all airline
> > companies decide not to have any of their planes in the air on the night of
> > 31 December 1999! But please tell me if you are aware of the truth of this.

> This is the first time I have heard this. It has the feel of
> an urban myth, but I told Felix I'd check. Any thoughts?

Not quite true.

But ....

Some airlines like BA get in the range of 15 to 17 hours/day
of flight averaged over the lifetime of their 747-400s. This would
imply that two thirds of their 747-400s are in the air at any one time.

Smaller aircraft on shorter flights and possibly idle overnight
don't get this kind of flying usage figure - possibly reducing as
far as 30 to 40%.

There are problems with ground space at some airports and
there would be space problems if you suddenly decided that all
aircraft had to be grounded for 24 hours with many aircraft
ending up at alternative airports off their normal beaten track
because there would be no space at their normal points of
departure and arrival.