Eldreney/Flights — reverse-engineered prompt

Build me a simple flights web app. I want a clean site where someone can search and browse flights, filter by things like departure city, destination, and date, and open a flight to see the main details such as times and price. Please make it feel complete end to end, with the server side and the client side hooked up, sensible models and API endpoints, basic validation, and some sample data so it works right away. If there are already pieces in the project, reuse them and fill in the missing parts instead of starting over. Keep the UI straightforward and modern, and make sure the app runs locally without a lot of setup. If anything is unclear, look up the current docs online and follow the style that already fits this project.