Really? You "want" to develop a website that can collect passenger information, provide schedule information and collect money all by yourself? You have links to current schedule info I presume so that the user can select a valid flight? You have knowledge about ensuring secure transactions when getting credit card numbers and payments? You have previous programming experience and knowledge about all the things you are going to have to know in order to provide a useful and secure application?
Good luck - you're a better programmer than I and I've been doing it for over 30 years.
Sorry about being rather harsh, but you have no idea what you are thinking of taking on.
PS - If you're posting here you should be using:
error_reporting(E_ALL | E_NOTICE);
at the top of ALL php code while you develop it!