Citymapper - The ultimate transport app - iPhone / Android / Web.
Justfly - JustFly offers amazing deals to flights all around the world.
Captain Train - You are going to love buying train tickets
Orbitz - Book cheap airline tickets, hotel reservations, car rentals, vacations and travel deals on Orbitz.
TransSee - Real time transit prediction and bus tracker web app.
Trip.com - TRIP.COM: FLIGHTS & HOTELS is a hotel and flight booking app that makes it easy to find the best deals on accommodations and flights.