https://desktopapps.ryanair.com
https://desktopapps.ryanair.com/en-gb/res/stations
https://api.ryanair.com/aggregate/3/common?embedded=closures
https://api.ryanair.com/timetable/3/schedules/DUB/LGW/years/2016/months/11
https://www.ryanair.com/de/de.farefinder.json is an JSON file in which several picture paths are declared :)
https://desktopapps.ryanair.com/bg-bg/res/currencies
https://api.ryanair.com/discount/3/discounts
https://ryanair.com/ie/en.markets.json https://www.ryanair.com/content/ryanair.markets.json
https://desktopapps.ryanair.com/en-gb/checkin/checkinpassengers
@nudabagana - The website uses these API endpoints during the booking process, so you can look for these requests in a browser dev console (in Chrome: Developer Tools -> Network)
This serves as a good reference also:
https://postman.com/hakkotsu/workspace/ryanair