[paul.fr]

Those aeroplanes that write slogans or messages in the sky. How do they write their message so that it is legible when viewed at any angle?

[Soul Surfer]

The answer of course is that they arent but things like that are usually done at the coast or at an event where a lot of people are gathered and looking in a particular direction so the angle of view is limited

[neilep]

Well, it's just as well that they did not write the Magna Carta or the Declaration Of Independence in sky writing !

It would have been a silly decision to do so and I'm glad they decided against it .

Here's a free tip...do not employ a sky writing team to produce legal documents.