Thanks for this, really interesting question. Our community has pulled together research about this and has found that the UK government only reports on national emissions with there being little information about international footprints. That means flight emissions are commonly reported at a national level, including emissions from take off and landing rather than emissions from the whole flight. It seems this is the case in this particularly case. A more realistic air travel emissions have been calculated in our Low Carbon Transport Challenge (shared below) as 7% of total GHG emissions (international and national), so it really does matter if we’ve not taking flights.
In terms of overall pie chart for the planet check out the community created guide to reducing personal carbon emissions, there is a good breakdown there.
More input from others of course always welcome!!!