I've flow Jetstar many times in Japan. Never had any issue but best to understand the rules of any airline you fly. Things go wrong sometimes. Insurance is useful. Comfortable New planes. Generally pretty organised and well run. Reasonable priced but not always the Cheapest (read vanilla airline reviews if you want cheapest)

Osaka Kansai Airport to Naha, Okinawa airport. Do not use Jetstar. The service was horrible. Website declined my card so I went to another airline who would accept my debit card. (had the funds) Four days later they charged my card. I called to cancel because I already bought tickets from another airline and they told me that it was non refundable. When I explained that my card was declined and I never received a confirmation, they said "You might not have received the confirmation, but we did. So take it or leave it". When I tried to name change because the group members changed, they wanted to charge twice the value of the ticket purchased. I sent in a complaint to the website and got a response over a week later from someone saying the website often malfunctions during busy times of the year but still would not refund my money and that it was an unfortunate mistake This airline is absolutely horrible and the customer service is the worst. My first experience with Japanese customer service representative and they were unpleasant and not helpful. I will never use it again. Please use another airline.

I flew from Kansai Osaka to Naha Okinawa. The planes were new, great service and alot cheaper than other airlines servicing Okinawa.