Okay kiddo, do you know what airplanes are? They are big machines that can fly us from one place to another. Some of these airplanes are small and they are called regional jets.
Now, there are different companies that make these airplanes and they compete with each other to sell them to airlines so that they can use them for flying people like us. This competition is called competition in the regional jet market.
The companies that make these airplanes have to make sure they are good enough for the airlines to want to buy them. They have to make them safe, comfortable, and they need to be able to fly long distances without any problems.
Sometimes, when there are a lot of companies making these airplanes, they might have to make their airplanes cheaper or better than the others so that the airlines will choose them over the other companies' airplanes.
It's like when you and your friends are playing a game and you want to win. You have to be really good at the game and make sure you're playing better than your friends, so you can win. This is what the companies making regional jets do, they try to be better than their competitors so they can win and sell airplanes to the airlines.