Right, the 'flying board thing' is called a jetboard or hoverboard. One, you can't just press a few buttons and get it. You have to complete the jetboard challenge. Later on in the game, I think at the point when you have to hunt down the scouts, you'll gain the jetboard for keeps.
Invincibility is more fun when you know you earned it by getting enough precursor orbs. But if you're too lazy, then you can try this:
Press Up, Up, Up, Left, Down, Down, Down, Left, Up, Up, Up, Left, Right
I've never tried it but someone did write it down for me in case I gave up.