Carbon Monoxide depending on the type of fuel.
A percentage is a comparison of two numbers: only one is specified here.You could have CO2 released by aeroplanes as a percentage of:all gases released by aeroplanes,all greenhouse gases released by aeroplanes,all CO2 released - whatever the source,CO2 released from man-made sources.There are other comparators.
Sure. Nuclear power plants give off effectively no gases of any kind.
methane
Greenhouse gases and a nasty smell
yes.
O2 leaves from the stomata
It works because there is a part in the lungs called dioxandied that helps it give off carbon dioxide and other gases
The collective nouns for aeroplanes are a flight of aeroplanes or a squadron of aeroplanes.
runway
Not really - the gases they give off are mainly methane.
No, aluminum does not give off any toxic fumes that are harmful in anyway. It does not produce gases nor does it vaporize.
It helps them to get air under the wings its a much better take off