Reason not to fly a true
budget airline is they typically only have 1 or very few flights per day. So if the flight gets cancelled you stuck till the next one and that could be tomrrow. Airlines won't just change your flight as they are hoping another has to buy the seat at the higher price. If they don't, they typically will allow people on standby to take it. So if your friends are willing to wait, don't check in bags and go to the earlier flight and ask the gate agent to fly standby. If the seats are free they generally let you take the earlier flight. I do this all the time on business trips. I don't fly Jetblue so their rules may be different.