If you fly into places they serve, JSX is great. I went from Burbank to Boulder. Ca to Co. The Los Angeles staff was helpful and nice. I arrived early and sat in the lounge. It's a rather plain room, chairs, coffee/tea, and tables. Feels a bit like a break room for staff.
The plane was clean, albeit a bit old. Flight crew was great, checking in often, without being a pest. WiFi worked solid the entire flight.
The in flight service is an ecological nightmare. Everything has single use plastic. For a yogurt, I got a plastic spoon, knife, and fork. This on top of the plastic cup and two levels of plastic lids. A bottle of water was a tiny plastic bottle, and it soon felt bad to get anything more. My kid needs me to leave a planet to enjoy, not save.
The Colorado ground crew was good. One guy was outstanding. I believe his name was Connor. He went out of his way to acknowledge people and help them. I watched how he did this with his colleagues too. If I were hiring, he's the type of employee I would try to steal.
When I arrived into Boulder, the ground crew was less than pleasant, minus the previous mention. But when I flew out the entire ground crew was friendly and nice.
The lounge isn't. It's just the lobby for everything, not just JAX. The coffee/tea machines were not on and are little more than the smallest Kureg one can buy.
Back on the plane, service was top notch. We did leave two hours late. The plane was too heavy, given the luggage situation. (Some folks had a lot, and it looked heavy.). They got everyone's body weight and calculated if we were still too heavy. If we were, they would have to stay on the ground and burn off fuel. Great, more waste.
Thankfully, some skinny people saved us and we left, arriving home two+ hours late. So it goes, it was still better than dealing with the crowded airport. The people make this business, so I hope they are taken care of well. read more