Namco Bandai has today confirmed that Ace Combat Infinity, announced last month, is a free-to-play title and reiterated that the game will be a PS3 exclusive which will be released on PlayStation Network.
In the new teaser trailer, which you can see above, we learn that the game is set in the near-future allowing for giant flying aircraft carriers.
The game will also have a seemingly novel multiplayer mode which sees two cooperative teams work together to take down a common enemy but they're also competing with each other to inflict the most damage on that enemy.
As for what you will need to spend money on to unlock in the game, there's no word yet but presumably planes can be purchased.
Ace Combat Infinity is due for release on PlayStation Store "later in 2013".