The instructions are as follows:
Top left 1999; Top right 1996; Bottom right1993
- First fold on •, then fold on •• and then on •••, after removing the protective tape on the sticker.
They are also in Spanish, but that does not make it any clearer.
Please
do not be alarmed. Something of a rum & uncanny nature has occured
here, but it is all under control. Return soon for full sickbag satisfaction.
Spanair
Spain
Out of these
three, the most interesting for me is the grey one above. This is made
of a very thick, tough plastic. 
Obviously
they get masses of people being ill on their flights, as the complex instructions
on how to seal it shut makes it super safe to handle after use.
Update 2001
- Apart from something odd going on with this page... Spanair have changed
little from the '99 version, except they have added a logo to the bottom
of the sickbag. 
