Hello,
allow me to introduce myself. I'm web app developer with more than 10 year experience with data management applications like web portals (flight ticket portal), web dashboards for data management web apps.
Based on your short description, your project is similar to flight ticket search portals.
For developing I suggest to use PHP, AJAX with some external API. And optional database for storing data. This way will be possible to eliminate duplicate requests for the same combinations of “departure city-destination city-date”. There is a lot of API's for searching flights data. From the most known I recommend QPX from Google, Skyscanner or Skypicker. There are two variants of cooperation. First (QPX) where first 50 requests/month are for free and for each other you will pay 0.035USD. Second variant is affiliate program (Skypicker, Skyscanner). In that variant is possible to use API or widget from the vendor and you will receive some commissions from each finished flight ticket reservation (if you want also implement reservation process).
I’m not sure what will be the goal of your project. Only search information or make also reservations? In both or any other variant, I’m able to develop for you design and user interface for your app, engine for searching and comparing data and presentation results for end users.
I can offer my own test server for development.
If you have any question, don't hesitate to contact me.
Best regards
Petr Staffa