Okay kiddo, so you know how sometimes when we want to go on a trip, we have to get on an airplane? Well, sometimes the place we want to go is not very far away, so we don't need a big, huge airplane to take us there. That's where regional jets come in.
A regional jet is just a smaller airplane that is used to fly people to places that are not too far away. They are usually used by airlines to take people to smaller cities, like the ones that don't have big airports.
These little planes have fewer seats than the big airplanes you might see at the airport, but they can still get us to where we need to go. They are also often flown by pilots who are just starting out in their careers, so they are a great way for them to get experience.
So, that's what a regional jet is - a little airplane that takes us to the small cities we want to visit. Pretty cool, huh?