It is possible that explaining how a jet engine works, etc is over the heads of an 8th grader. You can bore anyone if you pump enough misunderstood words and concepts at them.

Kids at that age just want to see the "awesome" side of things. Talk about speed, altitude, weight and mass and try to equate it to things they know - school buses, mom's minivan, etc. The things that an 8th grader is familiar with is quite limited.

If an alien came down and through a bunch of terms at me and tried to explain how a hyper drive works, I'd probably be interested until I was lost. Perhaps this is what happened to the kids.

Aviation wouldn't be packed with the folks it is if it didn't have a following. The first folks to walk on Mars are in grade school right now, don't forget that. Perhaps one of them was in that very class.

Age and intellectual development will eventually allow those with the innate interest to work down into the detail level required to confront the actual subject.