In 1994, I went down the Grand Canyon and amongst the participants there was a couple from the East Coast and the man told me how much he envyed me for living 3 hours from Paris. (Since, it's become 1:30 hours by train).
I had to smile
I have a good friend at Le Bourget and have been there several times. When it's the airshow, things are not always that atttractive though:from the parking place to inside the place or from the airfield back to the parking it took us so long (in the heat without means to find shade) and the heat means we need to drink water while there are so few toilets...well, this time I didn't bother.
Next time should be by train (though 2 years ago it was by bus and the least expensive trip). And you must expect to stand and walk for 6 hours with very little shadow (as everybody thinks the same and seeks it). My relatives hate crowded places and I'm a little more tolerant but too crowded kills the fun.
But one thing about Paris that's interesting is that you can go there for one day and come back the same day for shopping or visiting (reasonable HST ticket), while you're required to spend at least one night in London (the Eurostar train ticket is ok but if you want to return back the same day (which you could) , it's business class and 3 times more expensive!
Why can't England encourage one day tourism?

Raoul