THE easy way to Le Bourget
I am sorry I have to disagree with Laurent re. the best to go the Musee de l’Air et de l’Espace in Le Bourget.
THE easiest way is to get on bus #350 in front of Gare de l’Est (center of Paris). For the cost of only 1 ticket, you will be dropped right in front of the musee’s entrance after a 20 minutes ride. Really easier than the RER+walk+bus way. Bus 350 depart evry 10-15 minutes.
To go back to Paris, exit the museum’s parking and take a right on the big boulevard. Walk 300 m to the roundabout. The bus stop in a few meters befors the roundabout.
Cheers
Xavier