For me personally the replacement has been
https://itunes.apple.com/us/app/the-...533365777?mt=8, which I tried for a few months before finally taking the plunge and getting the pro version,
https://itunes.apple.com/us/app/the-...499826209?mt=8.
the UI is not quite as simple as FT, but it syncs perfectly with Tripit, syncs to my iCloud calendar, sends the same kinds of push notifications, etc. Even has the same icon, lol. Paid version removes the ads. The codeshare scrolling can get annoying but honestly I don't spend that much time in the app itself for it to bother me that much.