Explaining My Absence to Beautiful Boy

I've always wonder whether my son knows what is happening when I'm gone for a week for business overseas.  He would ask everybody he knows "where is papa?" (爸爸呢？).  He would become a super sweet boy when I come back and full of 100% smiles.  When I came back from New York a month ago, first thing I asked him was "do you know where's papa gone?" and to my surprise he said "America!" (美國!), so I asked around the family and found out that grandma only told him just once that I went there and he remembered that super well!

Now I know what's missing in his cognition: how is my absence related to travel, business, plane and countries.  He knows airplane coz everytime he hear a plane pass by, he points to the sky and said "airplane" in English and looks at me, how sweet.  He knows the shape of an airplane too, but he doesn't know his papa goes to the airport and goes inside a plane and fly high into the sky for work.  So from my last Tokyo trip, I bought a 1:500 model plane and first thing I came back home I unveiled the plane and he was so happy!  I played with him showing him how I get into the plane and how it takes off and made sure he knows the sound and relate to his experience of hearing the plane from the sky.  It was a fantastic experience for both of us.  The drawing on my Moleskine is about relating to my son's cognition of a plane's sound, its look and my absence.
All these reminds me again of John Lennon's Beautiful Boy and the lyric "Life is what happens to you while you are busy making other plans".  This weekend is all about intimacy and love with him, he puts his hand on my shoulder and held close to me all time.  Beautiful boy!