As the comments already suggest, it's basically just in major. If you want to call it a mode, that would be Ionian, but it's pretty strongly based on dominant–tonic relationships, so I think "major" would be more accurate than "Ionian." (See What is the difference between C major and C Ionian?)
The opening is all based on the C-major collection, and it's a bit reminiscent of Terry Riley's "In C." Around 1:20, Conti introduces a couple of accidentals (among them B♭ and E♭), but this is really just a transition to what begins at 1:23, which is really D Dorian. But interestingly, this D Dorian includes the exact same pitches as C major. Thus he hasn't changed any pitches, only the tonal center. By about 1:45, he's already moving back to C major.
At 3:41, he moves to D major.
In short, this is all pretty standard tonal material. "That specific flying feel" is, in my opinion, due more to the instrumentation and motivic material than to any particular mode.
The Ionian mode is just the mayor scale, right? I thought the theme had some alterations, I'm dissapointed, haha. Thanks for your answer!
– P. C. Spaniel Jul 03 '18 at 02:11