To unlock the Regalia Type-F (flying car), first complete the story by finishing all 14 chapters and defeating the end-Boss. After completing the story, you can visit a lodging and call Umbra to visit the open world. Infiltrate the Formouth Garrison in Leide. When you go near the Garrison, you will see a new side quest called "Formouth Garrison" appear. You can do this as early as story Chapter 8, but the enemies are Level 50+. It is recommended to do this after the story when you are stronger. After completing the "Formouth Garrison" side quest, you will get a "Strange Engine" item. This will trigger the "Into Unknown Frontiers" side quest. All you have to do is deliver the part to Cindy at the Hammerhead outpost. There are actually three of these strange parts, but two are unmissable story unlocks (Warped Wings from the Garrison in Chapter 5, Unstable Stabilizer from the Garrison in Chapter 6, and Strange Engine from the "Formouth Garrison" side quest). Once you have done all of the above, Cindy will upgrade your Regalia with the Type-F modification, which is a fancy batmobile-styled car that you can fly like a jet. To get the "Regalia Pilot" trophy, put it in manual drive, gain some speed, and press B to take off. The only disadvantage is that you can only land on streets. Landing on terrain will crash your car and result in a game over screen. It is a fun vehicle to drive and makes navigating the world quicker.