Help with the difference between these two sentences

Sorry for the long title!
I recently purchased Rosetta Stone for learning Japanese, but I am stuck.
I am not sure the difference between these two sentences.
Hikooki no shita ni iru otokonoko
Hikooki no ue ni iru otokonoko
I know that Hikooki means "plane" and otokonoko means "boy" (I think) but I am unsure of the middle part.
In Rosetta Stone, it uses pictures to teach, and says what is in the pictures, but I am still unsure for these two.
Thanks for the help.

"Shita" and "ue" are opposites, and mean "below" and "above," respectively. Hence:

飛行機の下にいる男の子
hikouki no shita ni iru otoko no ko

means "the boy below the airplane" while

飛行機の上にいる男の子
hikouki no ue ni iru otoko no ko

means "the boy above the airplane."

The verb "iru" means "to be" (for animate entities), and is modifying "otoko no ko," while the "ni" after "ue" or "shita" indicates that the place where the boy is is below or above the airplane.

Does that make sense?

Thank you very much. Makes perfect sense. I couldn't, for the life of me, figure out what the difference was.

If I may make a slight suggestion, while Rosetta Stone comes highly acclaimed from various sources, a grammar companion such as a Barron's or any other basic grammar book may help supplement the program you're in. I've been studying for around a year and a half so my experience is limited, but that being said I cannot imagine trying to learn Japanese strictly through picture association and pimsleur (sp?). At some point a breakdown of what's happening behind the spoken word is needed in order for you to apply the basic rules and structures. If this isn't accomplished then making new language will be difficult; that is, saying something different than the phrases you've learned by rote won't come as easily.

You might already be doing this so excuse my presumptions but, just in case you're not, I recommend this in addition to what you're already doing.

Thanks for the advice. After just going through this, I see where this might be very useful.
I will be going to a bookstore soon!!