What I mean by 'Idea'

By 'Idea' I mean something practical. This might be an improvement or something new but it should be practical.
For example:
"We should all have jet packs."
While a great idea, it's not very practical.
If I had an idea on how to improve the thrust/weight ratio, then that would be a practical idea. That being the only real problem that would need to be solved for jet packs.