The client decided to do his own research and talk to some other agents, and put the project on the back burner. If you want to have an automated solution where you will get paid to sell travel packages with airline tickets you can't really do it yourself. You need to hook into an existing network where you can offer packages created by hotels, resorts, tour operators, cruise lines, and more.
The only way you can do on on the cheap is to create a site where the client can create packages and offer them online, but the actual sale would be done on the phone. In essence the website is just a glorified travel brochure / lead generator.
You can find WordPress websites with plugins that will allow you to build sites like this, but they are not tied to any actual booking database.