 These new, ultra-budget airlines make spirit look expensive. But are they worth it? So you can only fly certain days into pretty specific locations, but just look at those prices. The main problem is that these airlines have a very limited number of planes and routes, which means if you're delayed, like about 20% of flights, it might be for days, not hours. Also, they charge you if you want to choose your seat, any seat, or bring bags, any bags. But that's true on many airlines. So they might not be for everyone, but if you're traveling light, have flexible plans, and can eat before you board, they might be for you.